This system should not be used for small weak vines, whether the weakness is a characteristic of the variety or due to the nature of the soil. It is suited only to very vigorous varieties such as Emperor, Almeria, and the Persian grapes when growing far apart in rich, moist soil.
Periods of development.
The first year in the life of a vine is devoted to developing a vigorous root system; the next two or three years to building up a shapely trunk and head, and a like period to forming the full complement of arms. At the end of from five to nine years the framework of the vine is complete and should undergo no particular change of shape except a gradual thickening of trunk and arms.
There are, therefore, several periods in the life of the vine with varying objects, and the methods of pruning must vary accordingly. These periods do not correspond exactly to periods of time, so it may be misleading to speak of pruning a two-year-old or a three-year-old vine. One vine under certain conditions will reach the same stage of development in two years that another will reach only in three or four years under other conditions. The range of time of these periods is about as follows:
First period—Formation of a strong root system 1 to 2 years Second period—Formation of stem or trunk 1 year Third period—Formation of head 2 to 3 years Fourth period—Complete development of the arms 2 to 3 years Total time of formation of framework 6 to 9 years
Under exceptionally favorable conditions the first and second periods may be included in the first year and a completely formed vine may be obtained in five years.
For planting, cuttings, one-year-old rooted vines, or bench grafts are used. In all cases, they need some attention from the pruner.
The usual way to prune a good rooted vine of average size having a single cane at the top and several good roots at the bottom is to shorten the cane to one or two buds and the roots to two or four inches, according to their size. Shortening the cane makes the vine less liable to dry out before rooting and forces the growth from the lower buds which produce more vigorous shoots. The roots are shortened so that there will be no danger of the ends being turned upwards when planted. If they are to be planted in a large hole, they may be left as long as five or six inches; if to be planted with a crowbar or dibble, they must be cut back to half an inch.
If the rooted vine has several canes, all but one should be removed entirely, and this one shortened to one or two eyes. The one left should be that which is strongest, has the best buds, and is the best placed. Where a horizontal cane is left, it should be cut back to the base bud. Otherwise the main growth may occur at a higher bud and the vine will have a crook which will result in a badly formed trunk.
If canes are growing from different joints, it is usually best to leave the lower cane if they are equally vigorous. This brings the buds from which growth will come nearer to the roots, and leaves less of the original cutting, which are advantages. The upper joint between the canes is, moreover, often more or less decayed or imperfect.
First growing season.
The treatment during the first spring and summer will depend on what growth the vines are expected to make and on whether the vines are staked the first year.
With cuttings and with both rooted vines and grafts where the growth will be moderate, staking the first year is unnecessary, though it has some slight advantages. In these cases, no pruning of any kind is necessary until the winter following the planting, except in the case of bench grafts. The pruning in the last case is confined to the removal of the suckers from the stock and roots from the cion. If the stocks have been well disbudded by the nurseryman, few suckers will develop. In moist soil, the cion roots may develop vigorously and must be removed before they grow too large, or they may prevent the proper development of the resistant roots.
The removal of roots should usually be done some time in July. For this purpose the hill of soil is scraped away from the union and after the cion roots and suckers are removed it is replaced. In this second hilling up, the union should be just barely covered so that the soil round the union will be dry and unfavorable to a second growth of roots. Later in the season, about September, the soil should be removed entirely from around the union and any new roots that may have formed removed. The union is then left exposed to harden and mature, so that it will pass the winter without injury.
First winter pruning.
At the end of the first growing season, an average good vine will have produced from three to five canes, the longest of which will be from two to three feet long.
Soon after the leaves have fallen in December or early in January the vines should be pruned. The method is precisely similar to that used for rooted vines before planting except that the main roots are not touched. All the canes are removed entirely except one. This one should be well matured, at least at the base, and should have well-formed eyes. It is shortened to two eyes. It is well also to cut off all shallow roots within three or four inches of the surface. This is necessary in the case of grafted vines if any have escaped the summer root-cutting.
Some of the vines may have made an exceptionally large growth. Such vines may sometimes possess a cane large enough from which to start the trunk in the way described later for the second winter pruning.
If the vines have not been staked before, the stakes should be driven soon after pruning and before the starting of the buds.
In order to preserve the alignment of the vineyard, the stakes should be driven on the same side of every vine at a uniform distance. The best distance is about two inches. If driven closer they may injure large roots or even the main underground stem if the vines have not been carefully planted vertically or slanting towards the side on which the stake is to be placed.
The side on which the stake should be placed depends on the direction of the prevailing winds during the growing season. This side is the leeward. That is, the stake should be so placed that the wind will press the vine towards the stake instead of away from it. This will much facilitate the work of keeping the vine upright and attached to the stake. If the vine is on the other side the pressure of the wind will stretch the string tight and the swaying of the vine will gradually wear the string until it breaks, necessitating retying. By carefully observing this rule, very few vines will require retying even if weak material like binding twine is used.
Second summer pruning.
Before the starting of the buds, in the spring following the planting, most of the vines appear about the same as when they were planted. There is, however, a very notable difference, in that they have well-developed root systems in the soil where they were formed. The result is that they make a much more prompt and early start and will produce a much larger growth than they did the first season. For this reason they require very careful attention from the pruner during the spring and summer of the second season. Vines neglected at this time, in this respect, may make as large a growth, but a large part of it will be wasted, the vines will be misformed and it will require from one to two years longer to develop a suitable framework and to bring them into bearing, even though they are properly handled during subsequent years. The more vigorous the vines, the more necessary it is to handle them properly during this period.
The main object during this second growing season is to develop a single, strong, vigorous and well-ripened cane from which to form the permanent trunk of the vine.
This is done by concentrating all the energies of the vine into the growth of a single shoot. As soon as the buds start, or when the most precocious has developed a shoot of a few inches in length, the vines should be disbudded. This consists in rubbing off with the hand all buds and shoots except the two largest and best placed. The lowest, upright shoots are usually the best. Leave only those which will make a straight vine. It is better to leave less developed buds than a shoot which, when it grows, will make an awkward crook with the underground stem.
After this disbudding, the two shoots left will grow rapidly, as they receive all the energies of the root system. When the longest have grown from ten to fifteen inches, they should be tied to the stake. Unless this is done, they are liable to be broken off by any heavy wind, owing to their soft, succulent texture. Only the best placed and most vigorous of the two shoots should be tied up. If this shoot is growing upright and near the stake, this can be done without any danger of injuring it. In this case the second shoot should be removed. If the shoot has to be bent over in tying it to the stake it may be injured. In such a case the second shoot should be allowed to grow until it is known whether the first has been injured. In case of injury the second shoot can be tied up the next time the vines are visited and the injured shoot removed.
At the tying up of the reserved shoots, all new shoots which have developed since the first disbudding should be removed. The shoots should be tied up loosely, as they are soft and easily injured, and they should be brought around carefully to the windward side of the stake.
The shoots will require tying once more when they have grown another foot or eighteen inches. There will then be two ties, one at two or three inches from the top of the stake and the other at about the middle. If the vines have a tall stake and are to be headed very high, another tying higher up may be needed later.
With vines making only a moderate growth, no other pruning will be needed until the winter. Exceptionally vigorous vines, however, may make a cane eight, ten or more feet long. Such a cane is heavy and is very likely to break the ropes by which it is attached to the stake. In this case it may break off at the bottom, or at least will form an awkward crook near the ground when it matures. In either case it is difficult to form a good trunk the following year. Even when the ties do not break, the cane will not be well suited for the commencement of a trunk, as the joints will be so long that it will be impossible to leave enough well-placed buds at the winter pruning.
Both these difficulties are avoided by timely topping. When such vigorously growing canes have grown twelve or eighteen inches above the top of the stake they are cut back about level with the stake. This is most conveniently done with a long-bladed knife or piece of split bamboo. After topping, the cane ceases to grow in length and laterals start at most of the joints. It is less exposed to the action of the wind, and the laterals supply the buds needed for forming the vine at the winter pruning.
The result of the second season's growth, then, has been to produce a single vigorous cane with or without laterals. This is the cane which is to develop into the final and permanent trunk of the vine. It must not only be large and vigorous, but must be properly matured. If the vine is allowed to grow too late in the season, an early frost may destroy the unmatured cane, and much of the results of the year's growth will be wasted. Such a frost may indeed kill the entire vine. Grafted vines are particularly liable to injury from this cause, as if they are killed down to the union they are completely ruined. Ungrafted vines when killed to the ground may be renewed from a sucker next year. This sucker, however, is likely to grow with such vigor that it is even more liable to injury from an autumn frost than the original shoot.
This late growth is much more likely to occur with young vines than with old. The old vines stop growing earlier because their energies are directed into the crop, and as they produce a larger amount of foliage they draw more upon the moisture of the soil, which therefore dries out earlier.
Late growth of the young vines must be prevented and the wood matured before frost if possible. This is accomplished by means which promote the drying of the soil in autumn. Late irrigations should be avoided. Cultivation should usually stop by midsummer. In very moist, rich soils, it is often an advantage to grow corn, sunflowers or similar crops between the rows of vines to take off the surplus moisture. In some cases it is good practice to let the summer weeds grow for the same purpose.
Second winter pruning.
With vines which have been treated as described and to which no accident has happened, the second winter pruning is very simple. It consists simply in cutting back the single cane which has been allowed to grow to the height at which it is desired to head the vine.
The vine so pruned consists of a single cane which with the older wood at the base reaches nearly to the top of the stake, or fifteen inches. This if properly treated will develop into a vine with a trunk of about twelve inches, though this length can be modified slightly, as will be explained later.
This cane consists of about seven or eight joints or internodes, with an equal number of well-formed eyes and an indefinite number of dormant buds, principally near the base of the cane or junction of the one- and two-year-old wood. Only the buds on the upper half of this cane will be allowed to grow. These buds—about four—should give six to eight bunches of grapes and four, six, or eight shoots from which to form the spurs at the following winter pruning.
With a vine which has been cut back to form a high head, the cane is about twenty-four inches long and can be used to form a trunk eighteen inches high, though this height can be modified as in the last case. As with the shorter cane, only the buds on the upper half will be allowed to produce shoots. These—about six—should give ten to twelve bunches and the shoots necessary for the formation of spurs.
In all cases a full internode has been left above the top bud. This is done by cutting through the first bud above the highest which it is desired to have grow. This cut is made in such a way as to destroy the bud but to leave the diaphragm intact and part of the swelling of the node. This upper internode is left partly to protect the upper bud, but principally to facilitate tying. By making a half-hitch around this internode, the vine is held very firmly. If the swelling at the node of the destroyed bud is not left, many vines will be pulled out of the hitch when they become heavy with leaves and supple with the flow of sap in the spring.
In tying the vines, no turns or hitches must be made around any part except this upper internode. A hitch below the top bud will result in a crook-necked vine, as the top will bend over in the summer under the weight of the foliage. A hitch lower down is even more harmful, as it will girdle and strangle the vine.
A second tie about half way from the upper to the ground is always necessary to straighten the cane. Even if the cane is straight when pruned, a second tie is needed to keep it from curving under the pressure of leaves and wind in the spring. For high-headed vines three ties are usually necessary.
For the top tie, wire is particularly suitable. It holds better than twine and does not wear. Even though it is not removed, it does no harm, as the part around which it is wound does not grow. The lower ties should be of softer material, as wire has a tendency to cut into the wood. They should be placed so that the cane is able to expand as it grows. With thin and especially with round stakes this means that the tie must be loose. With large, square stakes there is usually sufficient room for expansion, even when the twine is tied tight.
Third summer pruning.
During the third season, average well-grown vines will produce their first considerable crop and develop the canes from which will be formed the first arms.
Such a vine, soon after the starting of the buds in spring, will have one vigorous shoot about three inches long grown from the old wood and five fruit buds started above on the cane. All the buds and shoots below the middle of the cane should be removed.
This will leave the four or five fruit buds and will give the vine the opportunity to produce eight or ten bunches of grapes. These buds will produce also at least four or five shoots. If the vine is very vigorous and the season favorable, they may produce eight, ten or more.
When the five shoots grow, the height of the head will be determined at the next winter pruning by which of the corresponding canes are left as spurs. If the highest two canes are cut back to spurs and all others removed, the vine will be headed as high as possible, as these two spurs form the two first arms which determine the length of the trunk. If the lowest two canes are chosen and all of the vine above them removed, the trunk will be made as low as possible. Intermediate heights can be obtained by using some other two adjacent canes and removing the rest. It is often advisable to leave some extra spurs lower than it is desired to head the vine and to remove these lower spurs the following winter after they have borne a crop. For example, the three or four upper canes might be left, if the vine is vigorous enough, and the lowest one or two of these removed at the next pruning. This, however, is not often necessary with properly handled vines and is objectionable because it makes large wounds in the trunk.
Third winter pruning.
At the end of the third season's growth the vine should have a straight, well-developed trunk with a number of vigorous canes near the top from which to form the arms.
Figure 28 represents a well-grown vine at this period. No shoots have been allowed to grow on the lower part of the trunk and the five buds allowed to grow above have produced nine vigorous canes. The pruner should leave enough spurs to supply all the fruit buds that the vine can utilize. The number, size and thickness of the canes show that the vine is very vigorous and can support a large crop. It will depend somewhat on the variety how many buds should be left. For a variety whose bunches average one pound, and which produces two bunches to the shoot, twelve fruit buds should give about twenty-four pounds, or about seven tons per acre, if the vines are planted 12 by 6 feet, as these were. The number of spurs will depend on their length. Six spurs of two buds each will give the required number, but as some of these canes are exceptionally vigorous they should be left a little longer, in which case a smaller number of spurs will suffice.
When the number and length of the spurs are decided on, the canes should be chosen which will leave these spurs in the most suitable position for forming arms. This position will depend on whether we want a vase-form or fan-shaped vine. In the first case, we choose those which will distribute the spurs most evenly and symmetrically on all sides, avoiding any which cross or point downwards.
In the second case, we choose only those canes which run in the direction of the trellis, avoiding canes which stick out between the rows. Downward pointing canes may be used in this case.
Figure 29 shows the vine after pruning for a vase-formed head. The pruner has used two of the strongest canes to form two three-bud spurs and three of medium vigor to form three two-bud spurs. The head is of good shape, though some of the spurs are a little too low. One, two, or three of these can be removed at the following winter pruning, and the permanent arms and head of the vine formed from canes which develop on the two highest spurs. If the vine were too high, the head could be developed the next year from the three lowest spurs and the upper part removed.
Figure 30 shows vines of the same age of practically perfect shape. Less spurs have been left because the vines were less vigorous. It is easier to properly shape vines which make only a moderate growth during the first three seasons. On the other hand, very vigorous vines can finally be brought into practically perfect shape and the somewhat larger and more numerous wounds necessary are more easily healed by a vigorous vine.
Pruning after the third winter.
For the pruner who understands the pruning of young vines and has brought them to approximately the form represented in Figs. 29 and 30, the subsequent winter pruning is very simple. It involves, however, one new idea—the distinction between fruit and sterile wood.
Up to the third winter pruning, this distinction is not necessary; first, because practically all the wood is fruit wood, and second, because the necessity of forming the vine controls the choice of wood. From this time on, however, this distinction must be carefully made. At each winter pruning a number of spurs of fruit wood must be left to produce the crop to be expected from the size and vigor of the vine. Besides these fruit spurs, it may be necessary to leave spurs of sterile wood to permit of increasing the number of fruit spurs the following year.
This will be made clear by comparing Figs. 30 A and 31. Figure 30 A shows a vine at the third winter pruning with two fruit spurs of two buds each and one fruit spur of one bud—five fruit buds in all.
If these five fruit buds all produce vigorous shoots during the following summer, they will supply five canes of fruit wood which can be used to form five fruit spurs at the following winter pruning, which will be about the normal increase necessary. Some of these fruit buds, however, may produce weak shoots or shoots so badly placed that they would spoil the shape of the head if used for spurs. Other shoots, however, will be produced from base, secondary and adventitious buds which, while less fruitful, can be used to form spurs for the starting of new arms.
Figure 31 shows a vine after the fourth winter pruning which had developed from a vine similar to that shown in Fig. 30 A. From the three fruit spurs left the previous year four canes have been chosen for the fruit spurs of this year. The old spur on the left has furnished two new spurs and the two old spurs at the right each one new spur. The pruner, judging that the vine is sufficiently vigorous to stand more wood, has formed two spurs from water sprouts which, while not likely to produce much fruit the first season, will supply fruit wood for the following year. The result is a very well-shaped vine with six almost perfectly balanced spurs. These spurs will develop into permanent arms, some of them furnishing finally two or three.
Figure 32 shows a high-headed vine of the same age. It has five spurs, of which four are fruit spurs and one a spur of sterile wood left to shape the vine. The two more or less horizontal spurs on the right will bear fruit the following autumn and will be removed entirely at the following winter pruning, as they are badly placed. The arms of the vine will then be developed from the three upright spurs, which are excellently placed.
Each year thereafter the same process must be followed. First, enough fruit spurs, as well placed as possible, must be left to produce the crop. Second, on most vines supplementary spurs of sterile wood must be left to supply more arms where they are needed, and finally, when the full complement of arms has developed, to supply new arms to replace those which have become too long or are otherwise defective.
With headed vines, the treatment up to the third winter is the same except for the variations in the height of the head. At the third winter pruning, however, the formation of the head commences, and the pruner determines whether it shall be vase-formed or fan-shaped. The production of a vase-formed head has already been described.
At the third winter pruning, the vine should be pruned to two spurs, as shown in Fig. 30 B. More vigorous vines should not be given more spurs, as in Figs. 29 and 30 A, but the spurs should be made longer, with four, five, or even six eyes in some cases. This is in order to obtain some fruit, which might not be obtained from long pruning varieties by leaving many spurs. With extremely vigorous vines one fruit cane may be left at this pruning. The wires of the trellis should be put up this year, if this has not already been done.
Fig. 33 A and 33 B illustrates the second step in the production of a fan-shaped head. This form of head is used only for trellised vines and long-pruned varieties. The formation of the head and the management of the fruit canes are therefore conveniently discussed together.
By comparing the pruned vine, Fig. 33 B, with the unpruned, Fig. 33 A, the method of pruning will be made clear. The unpruned vine shows two arms, the spurs of the previous year, from one of which have grown three vigorous canes and from the other two somewhat less vigorous. The pruned vine shows a complete unit, that is, a fruit cane with its accompanying renewal spur on the vigorous side and a spur for the production of fruit wood for the following year on the other side. If the vine had been more vigorous two complete units would have been left and one or two extra spurs.
As the form of the vine is determined by the renewal spurs, special attention should be paid to their position. In this case, the middle cane on one arm and the lower cane on the other have been used for renewal spurs. This brings them both to the same height above the ground and determines the place of the permanent arms. The next year each of these spurs will furnish a fruit cane and one or two renewal spurs. The arms will thus in two or three years be increased to four, or, with very large vines, to six. These spurs should be chosen as nearly as possible in the plane of the trellis, that is, they should not project out sideways. Figure 25 shows vines of this kind of full size and in full bearing.
The fruit canes also should be as nearly as possible in the direction of the trellis, though this is not so important, as they can be bent over to the wire when tied up, and in any case they are removed the next year.
Some growers attempt to arrange the arms of their vines in two stages, one above the other, forming double-headed or two-crowned vines. The method is applied to both vase-formed and trellised vines. It is open to the same criticisms as the vertical cordon, the chief of which is that it cannot be maintained permanently. The lower head or ring of arms finally becomes weak and fails to produce wood.
It is easier to maintain in trellised vineyards and has some advantages, the chief of which is that it makes it easier to keep the vine in the single plane and to prevent arms getting into the inter-rows. The double trunk is not necessary and is, in fact, a disadvantage, as one trunk has a tendency to grow at the expense of the other.
Vertical and bowed canes.
Figure 24 A shows a long-pruned vine in which the fruit canes have been tied vertically to a tall stake. This is a method used commonly in many vineyards. The unit of pruning is the same as in the method just described, consisting of a fruit cane and a renewal spur. The framework of the vine consists of a trunk of medium height, with a vase-formed head consisting of three or four arms. The defects of this system have been pointed out on page 155.
It is used with fair success with seedless Sultanas and with some wine grapes such as Colombar, Semillon, Cabernet, and Riesling, in the hands of skillful pruners. The results with Sultanina are very unsatisfactory.
By this method, on most of the vines, the fruit canes start from high up near the middle of the stake, and are therefore too short for the best results. The canes which start from low down are in most cases suckers, and therefore of little value for fruit bearing.
Figure 24 B shows a vine with bowed canes. The method of pruning is exactly the same as in the method just described. The bowing of the canes, however, overcomes some of the defects of that method. It is used regularly in many wine grape vineyards of the cooler regions. It is unsuited for very vigorous vines in rich soil.
In head pruning, the treatment of young vines up to the second or third winter pruning is identical for all systems. In cordon pruning the treatment for the first and second is also the same. That is, the vine is cut back to two buds near the level of the ground until a cane sufficiently long to serve for the formation of the trunk is obtained.
In the vertical cordon the trunk is three to four feet long instead of one to two, as in head pruning. This makes it necessary to have a longer and more vigorous cane to start with. It may require a year longer to obtain this. That is to say, at the end of the second season's growth many vines will not have a single cane sufficiently developed to give the necessary three and one-half feet of well-ripened wood and properly developed buds. At the second winter pruning, therefore, it will often be necessary to cut the vine back to two buds, as at the first winter pruning.
Finally, a cane of the required length will be obtained. The vine is then formed as already described for the second winter pruning of headed vines, except that the cane is left longer. When such a vine is pruned, spurs are left at intervals along the trunk, as shown in Fig. 34. Each of these spurs is a fruit spur and is also the commencement of an arm. The future treatment of these arms is the same as that of the arms in head pruning.
During the first two or three years, vines which are to be given the form of horizontal cordons are treated exactly as for vertical cordons, that is, they are pruned back to two buds each winter and the growth forced by disbudding into a single cane during the summer.
As soon as a well-ripened cane of the required length is obtained, it is tied to a wire stretched horizontally along the row at from fifteen to twenty-four inches from the ground.
For this system of pruning, the rows should be twelve to fourteen feet apart and the vines six, seven, or eight feet apart in the rows. As the cordon or trunk of each vine should reach the next vine, it will have to be six to eight feet long. The best shape is obtained when the trunk is all formed one year from a single cane. It is necessary, however, sometimes to take two years for the formation of the trunk. In any case, the cane first tied down should reach at least half way to the next vine. The following year a new cane from the end of this should be used to complete the full length of the trunk.
In attaching the cane to the wire, it must be bent over in a gentle curve and care taken not to break or injure it. The proper form of the bend is shown in Figs. 27 and 35. Sharp bends should be avoided.
The cane should be placed on top of the wire, but should not be twisted around it. The end should be tied firmly and the rest of the cane supported by strings tied loosely in order to avoid girdling when the cane grows.
In the following spring, most of the buds on a good cane will start. If the cane is short jointed, some of the shoots should be removed and only those shoots allowed to develop which are conveniently situated for permanent arms. If the vines are to be short pruned, the arms should be developed every eight to twelve inches from a few inches beyond the bend to the extreme end. For long pruning, the arms should be farther apart, twelve to twenty inches. Shoots starting from the top of the cane and growing vertically upwards are to be preferred.
As the shoots develop, the strongest should be pinched repeatedly, if necessary. This will tend to force the growth of the weaker shoots and to equalize the vigor of all. At the end of the season, there should be from five to ten canes growing on each cordon of full length. These canes are then pruned back to two or three buds, or a little longer for long-pruned varieties.
During the following spring and summer, the vines should be carefully suckered and unnecessary water sprouts removed. Any shoots coming from the lower side of the cordon should be removed early to strengthen the growth in the shoots on the upper side. Such vines are apt to become dry or decayed on the upper side. At the end of this year, which should be the fourth or fifth from planting at the latest, the cordon will be fully formed and the final style of pruning can be applied. A short-pruned cordon vine is shown in Fig. 27. The arms and spurs are a little too numerous and too close together. If this vine required the number of buds shown it would have been better to have left the fruit spurs longer and to have left fewer and shorter wood spurs.
The upper vine of Fig. 35 shows a cordon pruned half long. This is an excellent system for Malaga, Emperor, and Cornichon when growing in very fertile soil. It gives the half-long fruit canes, which these varieties need to produce good crops. The fruit canes may be attached to a wire twelve or fifteen inches above the cordon or bent down and tied to the cordon itself, as in the lower vine of the figure. The first method is the more convenient, but the second is necessary where there is difficulty in obtaining satisfactory growth from the renewal spurs. When the fruit canes are tied down, as indicated in the lower vine, renewal spurs may not be needed, as vigorous shoots will usually be obtained from the lower buds of the fruit canes.
Choice of a system.
In choosing a system, we must consider carefully the characteristics of the particular variety we are growing. A variety which bears only on the upper buds must be pruned "long," that is, must be given fruit canes. It should be noted that many varieties, such as Petite Sirah, which will bear with short pruning when grafted on resistant roots require fruit canes when growing on their own roots. In general, grafted vines require shorter pruning than ungrafted. If pruned the same, the grafted vines may overbear and quickly exhaust themselves. This seems to be the principal reason for the frequent failure of Muscat vines grafted on resistant stock. The cultural conditions also affect the vine in this respect. Vines made vigorous by rich soil, abundant moisture, and thorough cultivation require longer pruning than weaker vines of the same variety.
The normal size of the bunch is also of importance. This size will vary from one-quarter of a pound to 2 or 3 pounds. It is difficult to obtain a full crop from a variety whose bunches are very small without the use of fruit canes. Spurs will not furnish enough fruit buds without crowding them inconveniently. On the other hand, some shipping grapes may bear larger crops when pruned long, but the bunches and berries may be too small for the best quality.
The possibilities of development vary much with different varieties. A Mission or Flame Tokay may be made to cover a quarter of an acre and develop a trunk four or five feet in circumference. A Zinfandel vine under the same conditions would not reach a tenth of this size in the same time. Vines in a rich valley soil will grow much larger than on a poor hillside. The size and shape of the trunk must be modified accordingly and adapted to the available room or number of vines to the acre.
The shape of the vine must be such as to protect it as much as possible from various unfavorable conditions. A variety susceptible to oidium, like the Carignane, must be pruned so that the fruit and foliage are not unduly massed together. Free exposure to light and air are a great protection in this respect. The same is true for varieties like the Muscat, which have a tendency to "coulure" if the blossoms are too moist or shaded. In frosty locations, a high trunk will be a protection, as the air is always colder close to the ground.
The qualities required in the crop also influence our choice of a pruning system. With wine grapes, even, perfect ripening and full flavor are desirable. These are obtained best by having the grapes at a uniform height from the ground and as near to it as possible. The same qualities are desirable in raisin grapes, with the addition of large size of the berries. With shipping grapes, the size and perfection of the berries and bunches are the most essential characteristics. The vine, therefore, should be so formed that each bunch hangs clear, free from injurious contact with canes or soil and equally exposed to light and air.
The maximum returns in crop depend on the early bearing of young vines, the regularity of bearing of mature vines and the longevity of the vineyard. These are insured by careful attention to all the details of pruning, but are possible only when the vines are given a suitable form.
The running expenses of a vineyard depend in a great measure on the style of pruning adopted. Vines of suitable form are cultivated, pruned and the crop gathered easily and cheaply. This depends also both on the form of vine adopted and on care in details.
It is impossible, therefore, to state for any particular variety or any particular location the best style of pruning to be adopted. All that can be done is to give the general characteristics of the variety and to indicate how these may be modified by grafting, soil or climatic or other conditions.
The most important characteristic of the variety in making a choice of a pruning system is whether it normally or usually requires short, half-long, or long pruning. With this idea, the principal grapes grown in California, together with all those grown at the Experiment Station on which data exist, have been divided into five groups in the following list:
1. Varieties which require long pruning under all conditions.—Clairette blanche, Corinth white and black, Seedless Sultana, Sultanina white (Thompson's Seedless) and rose.
2. Varieties which usually require long pruning.—Bastardo, Boal de Madeira, Chardonay, Chauche gris and noir, Colombar, Crabbe's Black Burgundy, Durif, Gamais, Kleinberger, Luglienga, Marsanne, Marzemino, Merlot, Meunier, Muscadelle de Bordelais, Nebbiolo, Pagadebito, Peverella, Pinots, Rieslings, Robin noir, Rulaender, Sauvignon blanc, Semillon, Serine, Petite Sirah, Slancamenca, Steinschiller, Tinta Cao, Tinta Madeira, Trousseau, Verdelho, Petit Verdot, Waelcherisling.
3. Varieties which usually require short pruning.—Aleatico, Aligote, Aspiran, Bakator, Bouschets, Blaue Elbe, Beba, Bonarda, Barbarossa, Catarattu, Charbono, Chasselas, Freisa, Frontignan, Furmint, Grand noir, Grosseblaue, Green Hungarian, Malmsey, Mantuo, Monica, Mission, Moscatello fino, Mourisco branco, Mourisco preto, Negro amaro, Palomino, Pedro Zumbon, Perruno, Pizzutello di Roma, Black Prince, West's White Prolific, Quagliano, Rodites, Rozaki, Tinta Amarella, Vernaccia bianca, Vernaccia Sarda.
4. Varieties which require short pruning under all conditions.—Aramon, Burger, Chardonay, Chauche gris and noir, Colombar, Crabbe's Black Burgundy, Durif, Black Morocco, Mourastel, Muscat of Alexander, Napoleon, Picpoule blanc and noir, Flame Tokay, Ugni blanc, Verdal, Zinfandel.
5. Varieties of table grapes which usually require half-long or cordon pruning.—Almeria (Ohanez), Bellino, Bermestia bianca and violacea, Cipro nero, Dattier de Beirut, Cornichon, Emperor, Black Ferrara, Malaga, Olivette de Cadenet, Pis-de-Chevre blanc, Schiradzouli, Zabalkanski.
These lists must not be taken as indicating absolutely for all cases how these varieties are to be pruned. They simply indicate their natural tendencies. Certain methods and conditions tend to make vines more fruitful. Where these occur, shorter pruning than is indicated may be advisable. On the other hand, other methods and conditions tend to make the vines vigorous at the expense of fruitfulness. Where these occur, longer pruning may be advisable.
The more usual factors which tend towards fruitfulness are:
Grafting on resistant vines, especially on certain varieties such as those of Riparia and Berlandieri;
Old age of the vines;
Mechanical or other injuries to any part of the vine;
Large development of the trunk, as in the cordon systems.
The more usual factors which tend towards vigor at the expense of fruitfulness are:
Rich soil, especially large amounts of humus and nitrogen;
Youth of the vines;
Excessive irrigation or rainfall (within limits).
In deciding what system of pruning to adopt, all these factors, together with the nature of the vine and the uses to which the fruit is to be put, must be considered. It is best when the vineyard is started to err on the side of short pruning. While this may diminish slightly the first one or two crops, the vines will gain in vigor and the loss will be made up in subsequent crops. If the style of pruning adopted results in excessive vigor of the vines, it should be gradually changed in the direction of longer pruning with the object of utilizing this vigor in the production of crop.
This change should be gradual, or the risk is run of injuring the vitality of the vines by one or two excessively heavy crops. Finally, each year the condition of the individual vine should determine the kind of pruning to be adopted. If the vine appears weak, from whatever cause, it should be pruned shorter or given less spurs or fruit canes than the year before. On the contrary, if it appears unnecessarily vigorous, more or longer spurs or fruit canes should be left. Every vine should be judged by itself. It is not possible to give more than general directions for the pruning of the whole vineyard. It cannot be well pruned unless the men who do the actual pruning are capable of using sufficient judgment to properly modify their methods for each individual vine.
EUROPEAN GRAPES IN EASTERN AMERICA
As we have seen, there were many efforts to grow European grapes in America during the first two centuries in the settlement of the country. The various attempts, some involving individuals, others corporations and in early days even colonies, form about the most instructive and dramatic episodes in the history of American agriculture. All endeavors, it will be remembered, were failures, so dismally and pathetically complete that we are wont to think of the two hundred years from the first settlements in America to the introduction of the Isabella, a native grape, as time wasted in futile culture of a foreign fruit. The early efforts were far from wasted, however, for out of the tribulations of two centuries of grape-growing came the domestication of our native grapes, one of the most remarkable achievements of agriculture.
The advent of Isabella and Catawba wholly turned the thoughts of vineyardists from Old World to New World grapes. So completely, indeed, were viticulturists won by the thousand and more native grapes, that for the century which followed no one has planted Old World grapes east of the Rockies, while vineyards of native species may be found North and South from the Atlantic to the Pacific.
Meanwhile, much new knowledge has come to agriculture, old fallacies have received many hard knocks and chains of tradition in which the culture of plants was bound, have been broken. In no field of agriculture have workers received greater aid from science than in viticulture. Particularly is this true of the diseases of the vine. The reports of the old experimenters were much the same, "a sickness takes hold of the vines and they die." What the sickness was and whether there were preventatives or remedies, no one knew a hundred years ago. But in the last half century we have learned much about the ills of grapes and now know preventatives or remedies for most of them. We know also that the early vine-growers failed, in part at least, because they followed empirical European practices. Is it not possible that with the new knowledge we can now grow European grapes in eastern America? The New York Agricultural Experiment Station has put this question to test, with results indicating that European grapes may now be grown successfully in eastern America. The following is an account of the work with this fruit at the New York Station.
EUROPEAN GRAPES AT THE NEW YORK EXPERIMENT STATION
In the spring of 1911, the Station obtained cuttings of 101 varieties of European grapes from the United States Department of Agriculture and the University of California. The cuttings obtained were grafted on the roots of a heterogeneous collection of seedlings, five years set, representing a half dozen species of Vitis. These stocks had little to recommend them except that all were vigorous, well established and all were more immune to phylloxera than the Old World varieties. From four to six grafts of each of the hundred varieties were made and a stand of 380 vines resulted, the percentage of loss being exceedingly small. The success in grafting was probably due to the method used, the value of which had been proved in previous work on the Station grounds. The method of grafting and details of care follow:
Details of care.
In grafting, the earth was removed from the plants to a depth of two or three inches. The vines were sawed squarely off below the surface of the ground. The stock was then split for a cleft graft. Two cions, made as described on page 46, were inserted in each cleft and tied in place with waxed string. Wax was not used as it does not stick in grafting grapes, because of the bleeding of the stock. After setting the cion, the earth was replaced and enough more of it used to cover stock and cion to prevent evaporation. This method of grafting is available to those who have old vineyards. It is so simple that the veriest tyro can thus graft grapes. Were young plants or cuttings used as stocks, some method of bench grafting would, of course, be resorted to.
The cultivation and spraying were precisely that given native grapes. There has been no coddling of vines. The fungous diseases which helped to destroy the vineyards and vexed the souls of the old experimenters were kept in check by two sprayings with bordeaux mixture; the first application was made just after the fruit set, the second when the grapes were two-thirds grown. Some years a third spraying with a tobacco concoction was used to keep thrips in check. Phylloxera was present in the vineyard but none of the varieties seemed to suffer from this pest. The stocks used were not those best suited either to the vines grafted on them or to resist phylloxera. Unquestionably some of the standard sorts used in France and California from Vitis rupestris or Vitis vulpina, or hybrids of these species, would give better results. From theoretical consideration, it would seem that the Vitis vulpina stocks should be best suited to the needs of eastern America.
It was thought by the old experimenters that European grapes failed in New York because of unfavorable climatic conditions. It was said that the winters were too cold and the summers too hot and dry for this grape. During the years the Station vineyard of Viniferas has been in existence, there have been stresses of all kinds of weather to which the variable climate of New York is subject. Two winters have been exceedingly cold, killing peach and pear trees; one summer gave the hottest weather and hottest day in twenty-five years; the vines have withstood two severe summer droughts and three cold, wet summers. These test seasons have proved that European grapes will stand the climate of New York as well as the native varieties except in the matter of cold; they must have winter protection.
To growers of American grapes, the extra work of winter protection seems to be an insuperable obstacle. The experience of several seasons in New York shows that winter protection is a cheap and simple matter. Two methods have been used; vines have been covered with earth and others have been wrapped with straw. The earth covering is cheaper and more efficient. The vines are pruned and placed full length on the ground and covered with a few inches of earth. The cost of winter protection will run from two to three cents a vine. Since European vines are much more productive than those of American grapes, the added cost of winter protection is more than offset by the greater yield of grapes. Trellising, also, is simpler and less expensive for the European grapes, helping further to offset the cost of winter protection.
It is apparent at once that European grapes must have special treatment in pruning if they are to be laid on the ground annually. Several modifications of European and California practices can be employed in the East to bring the plants in condition for winter laying-down. All methods of pruning must have this in common; new wood must be brought up from the base of the plant every year to permit bending the plant. This can be done by leaving a replacing spur at the base of the trunk. If two-eye cions are used when the plants are grafted and both buds grow, the shoot from the upper can be used to form the main trunk, while that from the lower bud will supply the replacing spur. Each year all but one of the canes coming from this spur are removed and the remaining one is cut back to one or two buds until the main trunk begins to be too stiff to bend down readily, then one cane from the spur is left for a new trunk and another is pruned for a new renewal spur.
The main trunk is carried up only to the lower wire of the trellis. At the winter pruning, two one-year canes are selected to be tied along this wire, one on each side, and the two renewal spurs chosen for tying up and new renewal spurs left. For the best production, different varieties require different lengths of fruit canes, but the work at Geneva has not progressed far enough so that recommendations can be made for particular varieties. It has been found best, however, to prune weak vines heavily and vigorous ones lightly. Under normal conditions, from four to eight buds are left on each cane, depending on the vigor of the vine. With some of the older seedlings used for stocks in 1911 which were so large that two cions were used, and in many of those where the roots seemed to have sufficient vigor to support the larger top, two trunks were formed, one from each graft. By spreading these into a V and making the inner arms shorter, very satisfactory results were secured.
The type of growth in Vinifera is different from that of native grapes. The young shoots which spring from the one-year canes, instead of trailing to the ground or running out along the trellis wires, grow erect. Advantage must be taken of this in the pruning system adopted in the East. The canes and the renewal spurs as described above are tied along the lower wire; then the young shoots which come from these grow upward to the second wire. When the shoots are four to six inches above this wire, they are pinched off just above the wire and any which have not already fastened themselves are tied to prevent the wind breaking them off. At the same time, if any of the axial buds on the shoots have begun to form secondary shoots, they are rubbed off, beginning with the node next above the upper cluster and going down to the old cane. This gives the cluster more room and better light. Soon after the first heading-back, the upper buds of the young shoot start lateral growth. The secondary branches usually grow upright and when they are several inches high they are topped with a sickle. This heading-back results in stockier and more mature canes for the following year, and if properly done adds to the fruitfulness of the vine and the fruit matures better.
The grower of European grapes grafted on American vines may be prepared to be surprised at the growth the vines make. At the end of the first season, the grafts attain the magnitude of full-sized vines; the second season they begin to fruit more or less abundantly, and the third year they produce approximately the same number of bunches as a Concord or Niagara vine; and, as the bunches of most varieties are larger than those of the American grapes, the yield, therefore, is greater. The European varieties, also, may be set more closely than the American sorts, since they are seldom such rampant growers.
It is too early to reason from this short experiment that we are to grow varieties of European grapes commonly in the East, but the behavior of the vines under discussion seems to indicate that we may do so. At the New York Station, the European varieties are as vigorous and thrifty as American vines and quite as easily managed. Why may we not grow these grapes if we protect them from phylloxera, fungi and cold? In Europe, there are varieties of grapes for nearly every soil and condition in the southern half of the continent. In eastern Europe and western Asia, the vines must be protected just as they must be protected here. It seems almost certain that from the many sorts selected to meet the various conditions of Europe, we shall be able to find kinds to meet the diverse soils and climates of this continent. And here we have one of the chief reasons for wishing to grow these grapes that American grape-growing may not be so localized as at present. Probably we shall find that European grapes can be grown under a greater diversity of conditions than native varieties.
The culture of European grapes in the East gives this region essentially a new fruit. If any considerable degree of success attends their culture, wine-making in eastern America will be revolutionized, for the European grapes are far superior to the native sorts for this purpose. Varieties of these grapes have a higher sugar- and solid-content than do those of the American species and for this reason, as a rule, keep longer. We may thus expect that through these grapes the season for this fruit will be extended. The European varieties are better flavored, possessing a more delicate and a richer vinous flavor, a more agreeable aroma, and are lacking in the acidity and the obnoxious foxy taste of many American grapes. Many consumers of fruit will like them better and the demand for grapes thus will be increased.
The advent of the European grape in the vineyards of eastern America ought to greatly increase the production of hybrids between this species and the American species of grapes. As we have seen, there are many such hybrids, but curiously enough scarcely more than a half dozen varieties of European grapes have been used in crossing. Most of these have been greenhouse grapes and not those that could be expected to give best results for vineyard culture. As we come to know the varieties best adapted to American conditions, we ought to be able to select European parents to better advantage than we have done in the past and by using them produce better hybrid sorts.
From the eighty-five varieties of European grapes now fruiting on the grounds of the New York Agricultural Experiment Station, the following are named as worth trying in the East for table grapes: Actoni, Bakator, Chasselas Golden, Chasselas Rose, Feher Szagos, Gray Pinot, Lignan Blanc, Malvasia, Muscat Hamburg, Palomino and Rosaki. These and other European grapes are described in Chapter XVIII; Chasselas Golden and Malvasia are illustrated in Plate V.
GRAPES UNDER GLASS
Grape-growing under glass is on the decline in America. Forty or fifty years ago the industry was a considerable one, grapes being rather commonly grown near all large cities for the market, and nearly every large estate possessing a range of glass had a grapery. But grapes are better and more cheaply grown in Europe than in America, and the advent of quick transportation permits English, French and Belgian grape-growers to send their wares to American markets more cheaply than they can be grown at home. For the present, the world war has stopped the importation of luxuries from Europe, and American gardeners ought to find the culture of grapes under glass profitable; they may expect also to be able to hold the markets for many years to come because of the destruction of Belgian houses and the shortage of labor in Europe resulting from the war.
Amateur gardeners ought never to let the culture of grapes under glass wane, since the hot-house grape is the consummation of the gardener's skill. Certainly the forcing of no other fruit yields such generous rewards. Grapes grown under glass are handsomer in appearance and better in quality than those grown out-of-doors. The clusters often attain enormous size, a weight of twenty to thirty pounds being not uncommon. The impression prevails that to grow grapes under glass, one must have expensive houses; this is not necessary, and "hot-house grapes" is a misnomer, the fruit really being grown in cold or relatively cool houses which need not be expensive. Grapes are grown under glass with greater ease and certainty than is imagined by those who form the opinion from buying the fruit at high prices in delicatessen stores. A grapery need not be an expensive luxury, and the culture of grapes under glass can be recommended to persons of moderate means who are looking for a horticultural hobby.
Almost any of the various modifications of greenhouses can be adapted to growing grapes. Firms constructing greenhouses usually have had experience in building graperies, and, as a rule, it will pay to have these professional builders put up the house. If the actual work is not done by a builder, it is possible to purchase plans and estimates, from which, if sufficiently detailed, local builders can work. On small places there is no doubt that the lean-to houses are most suitable, being inexpensive and furnishing protection from prevailing winds. These lean-tos should face the south and may be built against the stable, garage or other building; or better, a brick or stone wall to the north may be erected. It is possible to build a small grapery as a lean-to out of hot-house sash.
In commercial establishments and for large estates, where the grapery must be more or less ornamental, a span-roof house is rather better adapted to the grapery than a lean-to, especially if the house is not to be used for the production of grapes early in the season. On account of the exposure of the span-roof house on all sides, however, rather more skill must be exercised in growing grapes in them than in the better protected lean-to grapery. Whatever the house, it must be so constructed as to furnish an abundance of light, a requisite in which much is gained by having large-size glasses for the glazing. The glass must be of the best quality, otherwise the foliage and fruit may be blistered by the sun's rays being focused through defective spots.
Light, heat, moisture and good ventilation are all required in the grapery. Brick or stone are preferable to woodwork, as heat and moisture in the grapery are quickly destructive to wood foundations. If wood is used, only the most durable kinds should enter into the construction of the house. The under structure of masonry or of wood should be low, not higher than 18 inches or 2 feet before the superstructure of glass begins. The grapery must be well ventilated. There must be large ventilators at the peak of the house and small ones just above the foundation walls or in the foundation walls themselves. The ventilation should be such that the house can be kept free from draughts or sudden changes of temperature, as the grape under glass is a sensitive plant, and subject to mildew. Plenty of air, therefore, is an absolute necessity to the grapes, especially during the ripening of the fruit. The lower ventilators in graperies are seldom much used until the grapes begin to color, at which time the new growth, foliage and fruit are hardened, but from this time on upper and lower ventilators must be so manipulated that the houses are always generously aired.
Grapes can be forced in cold houses without the aid of artificial heat and formerly these cold graperies were very popular; but in the modern houses for growing this fruit, artificial heat is now considered a necessity, even though the heating apparatus may seldom be in use. For a finely finished product, a little heat to warm the room and dry the atmosphere may be absolutely necessary at a critical time, this often saving a house of grapes. Of heating apparatus, little need be said. Standard boilers for heating greenhouses with either steam or hot water are now to be purchased of many designs for almost every style and condition of house. Since the grapery seldom requires high heat, hot water is rather to be preferred to steam, although there is no objection to steam, especially if the grapery is a part of a large range of glass.
The border in which the vines are to be planted is the most important part of the grapery. All subsequent efforts fail if the border lacks in two imperatives, good drainage and a soil that is rich but not too rich. The grapery must be built on well-drained land or elevated above the ground to permit the construction of a properly drained border. "Border," in the sense of its being a strip or a narrow bed just inside the house, is now a misnomer, though the name undoubtedly comes from the fact that narrow beds inside the house were at one time used in which to plant vines. The border in a modern grapery now occupies all of the ground surface inside the house and may extend several feet outside the house.
Much skill is required in building the border. A good formula is: Six parts loamy turf from an old pasture; one part of well-rotted cow manure; one part of old plaster and one part of ground bone. These ingredients are composted and if the work is well done will meet very well the soil and food requirements of the grape. This formula can be varied according to soil conditions and somewhat in accordance with the variety planted. Unless natural drainage is well-nigh perfect, the border must be under-drained with tile and in any case a layer of old brick or stone is needful to make certain that the drainage is perfect. At least two feet, better three feet, of the border compost should be placed above the drainage material. In a border made as described, the grape finds ample root-run, but not too much, as in a surprisingly short time roots are found throughout all parts of this extensive border.
The care of the border is a matter of considerable moment and varies, of course, with those in charge. The usual procedure is to spade the outside border, if the border extends outside, before winter, after which it is covered with a coating of well-rotted manure, without any particular attempt having been made to keep out the frost, as a certain amount of freezing outside of the house is held to be beneficial. The inside border must be spaded just before the vines are started in the spring, having been covered previously with well-rotted manure. The time at which the vines are to be started in growth is determined by whether an early or a late crop of grapes is wanted. For an early crop, the vines must be started early in February; for a late crop, a month or even two months later suffices. So started, the first crop of grapes comes on in June or July, the later ones following in August or September.
It is related that Napoleon I, to secure saltpetre for making gunpowder, composted "filth, dead animals, urine and offal with alternate layers of turf and lime mortar," and asserted that "a nitre-bed is the very pattern of a vine-border" and that "when the materials have been turned over and over again for a year or two they are in exactly the proper state to yield either gunpowder or grapes." Napoleon's niter-bed is not now considered a good model for a grape-border, as the fruit produced in so rich a soil, though abundant, is coarse and poorly flavored, and the vines complete their own destruction by over-bearing. Gardeners hold that a grape-border may be too rich in plant-food, especially too rich in nitrogen.
Out of the 2000 or more Vinifera grapes, probably not more than a score are grown under glass, and of these but a half dozen are commonly grown. Black varieties have the preference for indoors, especially if grown for the market, where they bring the highest prices. They are also as a rule more easily handled indoors than the white sorts. However, as we shall see, one or two white kinds are indispensable in a house of any considerable size.
Of black grapes, Black Hamburg carries the palm of merit because it is most easily grown, best stands neglect, is a heavy producer, sets its fruit well, the grapes mature early; and, in particular, it meets the requirements of the unskilled gardener better than any other grape. The clusters are not as large and the flavor not as good as that of some other sorts.
Muscat of Alexandria is the best of the white varieties. It is, however, a hard grape to handle since it requires a high temperature to bring it to perfection, is a little shy in setting fruit and the grapes are not very certain in coming to maturity; it also requires a long season. A good quality is that it may be kept long after cutting, much longer than Black Hamburg.
For an earlier white grape, Buckland Sweetwater has much to recommend it; it ripens from two to three weeks earlier than Muscat of Alexandria and is much more easily grown. It is good in quality but not of high quality. Buckland Sweetwater may be well grown in the house with Black Hamburg, whereas it is almost impossible to grow Muscat of Alexandria in the same house with Black Hamburg.
Muscat Hamburg is a cross between Black Hamburg and Muscat of Alexandria, and is an intermediate in most fruit characters between these two standard sorts. It is not, however, very generally grown, although it well deserves to be because of its large, beautiful, tapering clusters of black grapes of finest quality.
Grizzly Frontignan adds novelty to luxury in the list of indoor grapes. The fruits are mottled pink in color, deepening sometimes to a dark shade of pink, and are borne in long, slender clusters. The grapes ripen early and are unsurpassed in quality but are, all in all, rather difficult to grow.
Barbarossa and Gros Colman are the two best late black grapes, especially for those who are ambitious to grow clusters of large size with large berries. Both are very good in quality. Neither of the two is particularly easy to grow, since they require a long time to ripen; but, to offset this, both keep longer than any other sorts after ripening. Because of the large size of the berries, thinning must begin early and must be rather more severe than with other grapes. This variety is now largely grown in England for exportation to this country in early spring.
White Nice and Syrian are two white sorts which attain largest size in clusters, specimens weighing thirty pounds being not infrequent, but are coarse and poor in quality and are, therefore, hardly worth growing.
Alicante is a black sort often grown for the sake of variety, since it departs from the Vinifera type rather markedly in flavor. The grapes have very thick skins and may be kept longer than those of any other variety.
Lady Downs is another late-keeping black grape of highest quality, but difficult to grow. The bunches and berries are small in comparison with other standard sorts, characters that do not commend the variety to most gardeners.
Perhaps a dozen more sorts might be named worthy of trial in American graperies, but the list given covers the needs of commercial establishments and will meet the wants of most amateur growers.
PLANTING AND TRAINING
Two-year-old vines are most commonly planted. The vines are set inside the house at least a foot from the walls and four feet apart. The grapery must be built on piers with spaces of at least two feet between, and the vines are placed opposite these openings in the foundation. When planted, the vines are cut back to two or three buds, and when these start the strongest are selected for training, the others being rubbed off. The grapery must be strung with wires running lengthwise of the house at about fifteen inches from the glass. Greenhouse supply merchants furnish at a low price cast iron brackets to be fastened to the rafters to hold these wires. As the growing vines reach one wire after another, they are tied with raffia to hold them in place. Usually, young vines will reach the peak of the house by midsummer, and as soon as this goal is attained must be pinched so that the cane may thicken up and store food in the lateral buds for the coming season. When the wood is well matured, the vine is cut back to half or one-third its length, depending on the variety, laid on the ground and covered for the winter. An item of no small importance in winter care is to keep out mice, this pest being inordinately fond of grape buds, and once the buds are destroyed the vines are ruined for the coming season.
The second year's work is largely a repetition of that of the first. The vines are permitted to reach the peak of the house and are again stopped by pinching. A considerable number of laterals spring up on each side of the main vine, and these must be thinned as they develop to stand at the distance apart of the wires to which they are fastened. This is pre-supposing that the gardener has chosen the spur method of pruning, the method generally used in America and the one, all things considered, which gives best results. The selection of the laterals the second year, therefore, is a matter of much importance since spurs are to be developed from them. Care should be taken to have these spurs regularly distributed over the length of the vine. This second year, grapes must not be permitted to develop on the terminal shoots, but a few clusters may be taken from the laterals in which case the laterals are pinched two buds beyond the cluster, the pinching continuing throughout the season if the laterals persist in breaking, as they will do in most cases. At the end of the season, the terminal is shortened at least one-half, and the laterals are pinched back to a bud as close as possible to the main stem. The vines are then put down for the winter as at the close of the first season.
The work of the third season is a repetition of that of the second, with the exception that the vine is permitted to fruit throughout its whole length, although not more than one pound of fruit to a foot of main vine is permitted. The plants are now established and the only pruning in this and succeeding years is to cut the laterals at the close of each season close to the main stem, leaving strong healthy buds of which at least one, usually more, will be found close to the stem. If more than one bud starts, only the strongest is chosen, although often an extra one is needed to fill a vacancy on the opposite side. After the third or fourth season, depending somewhat on the variety, two pounds of fruit or more to the foot of the main stem can be permitted. The novice, however, is likely to permit his vines to overbear with the result that the crop is cast, or the berries rattle, or the fruit turns sour before ripening. From the beginning to the finish of the season, in this method of pruning, much pinching of laterals is required. No hard and fast rule can be laid down for this pinching, but, roughly speaking, all new growth beyond the second joint from the cluster should be pinched out as fast as it shows. With most varieties, this means that the lateral is kept about eighteen inches from the main stem. After a few years, well-developed spurs form at the base of the original laterals, and from these spurs the new wood comes year after year.
An alternative method of pruning is to permit the new canes to grow up from a bud near the ground each season. When the vine is well established, this new cane is fruited throughout its entire length, the laterals being pinched as described under the spur method. This method of pruning is known as "the long cane method." Gardeners hold that they can grow better fruit with this than with the spur method, but the difficulties are greater and the crop is not as large.
CARE OF THE VINES
With the cultivation of all varieties indoors, more clusters set than the vines can carry. This means that a part of the clusters must be removed, an operation that depends on the variety and one that requires experience and judgment on the part of the gardener. Roughly speaking, half the clusters are taken, leaving the other half as evenly distributed on each side of the vine as possible. The time to take these clusters is also a delicate matter, since some sorts are shy in setting and the clusters must not be taken until the berries are formed and it can be seen how large the crop will be. As a rule, however, this thinning of clusters may be begun as soon as the form of the cluster can be seen.
It is very necessary also, especially with all sorts bearing large berries, that grapes be thinned in the cluster. The time to thin the cluster varies with the variety. Sorts which set fruit freely can be thinned sooner than those which are shy in setting. On the one hand, the thinning must not be done too soon as it cannot be told until the berries are of fair size which have set seed and which have not; however, if thinning is neglected too long, the berries become over-crowded and the task becomes difficult. The thinning is performed with slender scissors, and the bunches must not be touched with the hand, as touching impairs the bloom and disfigures the fruit. The clusters are turned and steadied by a small piece of pencil-shaped wood. Thinning is practiced not only to permit the berries to attain their full size but also to permit the bunches to attain as great size as possible. If too severely thinned, the clusters flatten out after maturity. This is especially the case when too many berries are taken from the center of the bunch. A large cluster of grapes is made up of several small clusters, making it necessary to tie up the upper clusters or shoulders of the bunch to permit the berries to swell without being thinned too severely. Grapes intended for long keeping require more thinning than those to be used at once after picking, since, in keeping, the berries mold or damp-off in the center of the bunch if it is too compact.
The vines in the grapery must be watered with considerable care. The amount of water to be used depends on the composition of the borders and the season of growth. If the border is loose and well-drained, the supply of water must be large; if close and retentive, but a small amount of moisture is required. Watering must not be done during the period of blossoming, since dry air is necessary for proper pollination. When the grapes begin to show color, the vines are heavily watered, after which little if any water is applied. Some gardeners mulch the vines with hay to retain the moisture in the house and keep the atmosphere dry.
Ventilating the grapery is another important detail of the season's work. Proper ventilation is difficult to secure in the early spring months when the dryness of the sun on the one hand, and cold air on the other, make it difficult to avoid draughts and regulate the temperature. Another troublesome time is when the grapes begin to color, as it is then necessary for the grapery to have air at night; but when too much air enters, there is danger from mildew. Towards the end of the season, all parts of the plant become harder in texture and the grapery may then be more generously aired. After the fruit is cut, the houses are ventilated in full so that the wood may ripen properly.
Several pests vex the gardener in growing grapes indoors. Of these, mealy-bug, red-spider, thrips and mildew are most troublesome. In a well-conducted grapery, there is never an intermission in the warfare against these pests.
Mealy-bug is usually a sign of sloth on the part of the gardener. In a grapery devoted exclusively to grape-growing, it should never be seen, but, since gardeners must often grow other plants in the grapery, mealy-bug sooner or later appears and is often hard to dislodge. It is best repelled by removing the loose bark on the trunks which harbor the pest and then washing with kerosene emulsion. When this becomes necessary, not only the vines but the rafters and all parts of the house should be sprayed with the emulsion.
Red-spider is another pest usually found in the grapery, but it thrives only in a dry atmosphere and is easily gotten rid of by syringing. As soon as red-spider appears in a house its appearance is usually known by the reddish tinge on the foliage; syringing should be kept up until the pest is disposed of, keeping the house damp in all except dull weather. Syringing is done only when plenty of air can be given and when it can be followed by sunlight so that the water remains on the vines as short a time as possible.
Thrips, another small insect, is sometimes troublesome but not often and is now easily controlled by applications of nicotine. Much care must be taken in the application of nicotine late in the season, otherwise the fruit will be injured.
The only fungous disease of the grape troublesome in the greenhouse is mildew. Mildew is usually brought on by a sudden change of temperature or by draughts in the grapery. Gardeners are of the opinion that east winds, in particular, give unfavorable conditions for mildew and prefer to open the ventilators to the west. If taken in time, mildew is easily kept in check by preventing the conditions which favor it, and by dusting the vines in dry sunshine with sulfur.
GRAPE PESTS AND THEIR CONTROL
In common with other cultivated fruits, grapes are at the mercy of numerous insect and fungous pests unless man intervenes with remedial or preventive treatment. Happily for viticulture, knowledge of the pests of the vine has made such advancement in recent years that practically all are now controlled by remedial or preventive measures. Possibly no field of agriculture has had greater need, or received greater aid from science in the study and control of insects and diseases than grape-growing. A separate treatise would be required to treat the pathological troubles of the grape fully; only such details of the life histories of the several pests to be discussed as are essential to a proper understanding of the control of the parasites can be given here.
Insects troubling the grapes are numerous, at least 200 having been described in America, most of which have their habitat on the wild prototypes of the cultivated vines of this continent. For this reason, with a few exceptions, the insect pests of the grape in America are widely distributed, abundant, and, therefore, often very destructive to vineyards unless vigorously combated. The many pestiferous species vary greatly in importance, depending on locality, weather and the variety. Phylloxera, however, the country over, is most common and deserves first attention.
This minute sucking insect (Phylloxera vastatrix), injures the grape by feeding on its roots. Decay usually follows its work on the roots and is often more injurious than the harm done directly by the parasite. This decay is always much more serious on European vines than on those of our native species. The phylloxera is a native of the United States east of the Rocky Mountains, from whence it was introduced into France and from France into California, where it causes much greater damage than elsewhere in the United States. Wherever the pest is found, it is more injurious in heavy than in sandy soils. In fact, in very sandy soils the vines are often sufficiently resistant to be practically immune.
The life history of the phylloxera is very complex where the different forms of the insect appear and need not be entered into in detail here. East of the Rockies, the most evident indication of the presence of the pest is great numbers of leaf-galls on the under side of the leaves of the grape as shown in Fig. 36. These galls, however, are seldom to be seen in California and are not present on Concords and some other varieties in the East. The winter egg may be taken as the beginning of the life cycle of the phylloxera. From a single winter egg a colony may arise, the first insect after hatching making its way to the leaves where it becomes a gall-maker and gives rise to a new generation of egg-laying root-feeders. On varieties and in regions where the gall form is not found, the insect probably goes directly from the winter egg to the roots. Once the pest is established on the roots, generation follows generation throughout the growing period of the vines, as many as seven or eight occurring in one season.
From midsummer until the close of the growing season, some of the eggs deposited by the root-feeders develop into nymphs which acquire wings and emerge from the soil to form new colonies from eggs deposited on the under side of the leaf. An individual insect deposits from three to six eggs of two sizes, from the larger of which come the females and these, after fertilization, move to the rough bark of the vine and deposit the winter egg for the renewal of the cycle.
Several methods of control have been employed in Europe and California, as treatment by carbon bisulfide injected in the soil; flooding in vineyards that can be irrigated; confining the vines to sandy soils; and, most important, planting vines grafted on resistant stocks, there being great variation in immunity of species of American grapes to phylloxera. The subject of stocks resistant to this pest has been discussed in Chapter IV and need not be taken up again. East of the Rockies, treatment is not necessary with American grapes.
The grape root-worm.
The grape root-worm is the most harmful of the insect pests of grapes in the grape-belt along the shores of Lake Erie in Ohio, Pennsylvania and New York. This root-worm (Fig. 37) is the larva of a grayish-brown beetle (Fidia viticida), shown in Fig. 38. The worms feed at first on the rootlets and later on the bark of the larger roots of the vines so that the injured plants show roots devoid of rootlets and bark channeled by the pest. So plain is the work of the root-worm that the grower never need be at a loss as to the cause of vines injured by this pest. The worms feed during the latter part of the growing season, reaching full growth at this time. The next June they transform into pupae and in late June or early July emerge as adult beetles.
The presence of the adult beetles is more easily detected on the foliage than is that of the larvae on the roots, for the feeding beetles ravenously devour the upper sides of the leaves, leaving chain-like markings, shown in Fig. 39, their destructiveness decreasing somewhat after a few days from their first appearance. A fortnight after the beetles begin their attack on the foliage the female begins laying her eggs, to the number of 200, placing them under the rough bark of trunk and cane. These hatch in late July or August and the young grubs at once seek the roots.
Two methods of control have been devised: destruction of the beetles before they lay their eggs; and destruction of the pupae while in the ground. When the beetles are present in large numbers, many of them may be destroyed by spraying with a mixture of cheap molasses and arsenate of lead, using molasses at the rate of two gallons to a hundred gallons of water and the arsenate of lead at the rate of six pounds. This should be followed by a second spraying a week later, using bordeaux mixture (4-4-50) and three pounds of arsenate of lead. This second spray serves to repel migrating beetles from the vines. The molasses spray is ineffective unless several days of fair weather follow the spraying, as rain washes the material from the foliage. Bordeaux mixture is not easily affected by rain. In moderately infested vineyards, bordeaux mixture and arsenate are used instead of molasses and arsenate of lead, followed in about ten days with a second application of the same material.
An effective method of reducing the number of beetles is the destruction of the pupae. This is best done by leaving a low ridge of earth under the vines at the last seasonal cultivation to remain until most of the larvae have pupated, and then be leveled with a horse-hoe and later with a harrow. The horse-hoe and harrow crush many of the pupae and break the cells of others to the great destruction of the pest. This latter method of control is not adequate in itself and in bad infestations both should be used. When the infestation is only moderate, this latter method is not advised, owing to the lateness of the time of horse-hoeing. It is good horticultural practice to horse-hoe the latter part of May or early June. To wait for the pupal stage of the root-worm delays the work until numerous small roots start which would be destroyed by the horse-hoe. Spraying will control a moderate infestation.
The grape-vine flea-beetle.
In the warm days of May and June when the buds of grapes are swelling, a shining steel-blue beetle may often be found in the vineyards of eastern America feeding on the tender buds of the grape. From its color the insect is often called the steely-beetle, and from its activity and habit of jumping it is known as the flea-beetle (Haltica chalybea). The vine is seldom seriously injured by this pest but many buds are destroyed, causing the loss of the fruit that should have developed from the buds. It is true that new buds often develop after the injury, but these, as a rule, produce only foliage.
The life history of the flea-beetle is such that the pest is not hard to control, the chief steps in its development being as follows: The beetles deposit small orange-colored eggs, cylindrical in form, illustrated in Fig. 40, about the buds and in crevices of the bark of the canes in May or June. Most of these eggs are hatched by the middle of June. The larvae feed upon the foliage until about July first and then crawl to the ground in which they form cells and pupate. The latter part of July the adults emerge and seek wild vines upon which they feed, entering hibernation rather early in the fall. The beetles hibernate under leaves, in rubbish and in the shelter of the bark of trees and vines, but emerge in the warm days the following spring to seek vineyards.