Part 1 (2/2)
next spring if the young growth seems to be too thick, or if the plant is weak. Each shoot will bear, on an average, two or three cl.u.s.ters.
Some shoots will bear no cl.u.s.ters. From one to six of the old canes, each bearing from five to ten buds, are left each spring. The number of cl.u.s.ters which a vine can carry well depends upon the variety, the age and size of the vine, the style of the training, and the soil and cultivation. Experience is the only guide. A strong vine of Concord, which is a prolific variety, trained upon any of the ordinary systems and set nine or ten feet apart each way, will usually carry from thirty to sixty cl.u.s.ters. The cl.u.s.ters will weigh from a fourth to a half pound each. Twelve or fifteen pounds of marketable grapes is a fair or average crop for such a Concord vine, and twenty-five pounds is a very heavy crop.
[Ill.u.s.tration: 2. THE BEARING WOOD.]
The pruning of the grape vine, therefore, is essentially a thinning process. In the winter pruning, all the canes of the last season's growth are cut away except from two to six, which are left to make the fruit and wood of the next year; and each of these remaining canes is headed back to from three to ten buds. The number and length of the canes which are left after the pruning depend upon the style of training which is practiced. A vine which may completely cover a trellis in the fall, will be cut back so severely that a novice will fear that the plant is ruined. But the operator bears in mind the fact that the grape, unlike the apple, pear and peach, does not bear distinct fruit-buds in the fall, but buds which produce both fruit and wood the following season.
[Ill.u.s.tration: 3. DIAGRAM.]
Let us now suppose, therefore, that we have pruned our vine in the fall of 1891 to two canes, each bearing ten buds. We will call these canes A and B, respectively. (Fig. 3.) In 1892, therefore, twenty shoots grow from them, and each of these shoots or new canes branches, or produces laterals. We will call these new canes of 1892, A 1, A 2, A 3, B 1, B 2, and so on. Each of the new canes bears at the base about two cl.u.s.ters of grapes, giving a total yield of about forty cl.u.s.ters. These cl.u.s.ters stand opposite the leaves, as seen in fig. 1. In the axil of each leaf a bud is formed which will produce a cane, and perhaps fruit, in 1893. If each of these new canes, A 1, A 2, etc., produce ten buds--which is a moderate number--the vine would go into the winter of 1892-3 with 200 buds for the next year's growth and crop; but these buds should be reduced to about twenty, as they were in the fall of 1891. That is, every year we go back again to the same number of buds, and the top of the vine gets no larger from year to year. We must, therefore, cut back again to two canes. We cut back each of the original canes, A and B, to one new cane. That is, we leave only A 1 and B 1, cutting off A 2, A 3, etc., and B 2, B 3, etc. This brings the vine back to very nearly its condition in the fall of 1891; but the new canes, A 1 and B 1, which are now to become the main canes by being bent down horizontally, were borne at some distance--say three or four inches--from the base of the original canes, A and B, so that the permanent part of the vine is constantly lengthening itself. This annually lengthening portion is called a _spur_. Spurs are rarely or never made in this exact position, however, although this diagrammatic sketch ill.u.s.trates clearly the method of their formation. The common method of spurring is that connected with the horizontal arm system of training, in which the canes A and B are allowed to become permanent arms, and the upright canes, A 1, A 2, B 1, B 2, B 3, etc., are cut back to within two or three buds of the arms each year. The cane A 1, for instance, is cut back in the fall of 1892 to two or three buds, and in 1893 two or three canes will grow from this stub. In the fall of 1893 only one cane is left after the pruning, and this one is cut back to two or three buds; and so on. So the spur grows higher every year, although every effort is made to keep it short, both by reducing the number of buds to one or two and by endeavoring to bring out a cane lower down on the spur every few years.
Fig. 4 shows a short spur of two years' standing. The horizontal portion shows the permanent arm. The first upright portion is the remains of the first-year cane and the upper portion is the second-year cane after it is cut back in the fall. In this instance, the cane is cut back to one fruiting bud, _b_, the small buds, _a a_, being rubbed out. There are serious objections to spurs in any position. They become hard and comparatively lifeless after a time, it is often difficult to replace them by healthy fresh wood, and the bearing portion of the vine is constantly receding from the main trunk. The bearing wood should spring from near the central portions of the vine, or be kept ”near the head,”
as the grape-growers say. In order to do this, it is customary to allow two canes to grow out each year back of the canes A 1 and B 1, or from the head of the vine; these canes may be designated C and D. (Fig. 3.) These canes, C and D, are grown during 1892--when they may bear fruit like other canes--for the sole purpose of forming the basis of the bearing top in 1893, while all the old top, A and B, with the secondary canes, A 1, A 2, B 1, B 2, B 3, etc., is cut entirely away. Here, then, are two distinct methods of forming the bearing top for the succeeding year: either from _spurs_, which are the remains of the previous top; or from _renewals_, which are taken each year from the old wood near the head of the vine, or even from the ground. Renewals from the ground are now little used, however, for they seldom give a sufficient crop unless they are headed in the first fall and are allowed to bear the second year. It should be borne in mind that the spur and renewal methods refer entirely to pruning, not to training, for either one can be used in any system of training. Spur pruning, however, is growing in disfavor amongst commercial grape-growers, and the renewal is more or less used in all systems of training.
[Ill.u.s.tration: 4. SPUR.]
Fig. 5 ill.u.s.trates a renewal pruning. This engraving shows the head of a vine seven years old, and upon which two canes are allowed to remain after each annual pruning. The portion extending from _b_ to _f_ and _d_ is the base of the bearing cane of 1892. In the winter of 1892-3, this cane is cut off at _d_, and the new cane, _e_, is left to make the bearing wood of 1893. Another cane sprung from _f_, but it was too weak to leave for fruiting. It was, therefore, cut away. The old stub, _b_, _f_, _d_, will be cut away a year hence, in the winter of 1893-4. In the meantime, a renewal cane will have grown from the stub _c_, which is left for that purpose, and the old cane, _b d_, will be cut off just beyond it, between _c_ and _f_. In this way, the bearing wood is kept close to the head of the vine. The wound _a_ shows where an old stub was cut away this winter, 1892-3, while _b_ shows where one was cut off the previous winter. A scar upon the back of the head, which does not show in the ill.u.s.tration, marks the spot where a stub was cut away two years ago, in the winter of 1890-1. This method of pruning can be kept up almost indefinitely, and if care is exercised in keeping the stubs short, the head will not enlarge out of proportion to the growth of the stock or trunk.
[Ill.u.s.tration: 5. RENEWAL PRUNING.]
_Pruning Young Vines._--The time required after planting to get the vine onto the wires or trellis varies with the strength of the vine when set, the variety, the soil and cultivation, and the system of training; but, as a rule, the training begins the second or third year, previous to which time the vine is pruned, not trained. Two-year-old vines are most popular for planting, although in the strong varieties, like Concord and Niagara, well-grown yearling vines are probably as good, if not better.
The strong-growing kinds are commonly set from eight to ten feet apart in the row, and the rows eight or nine feet apart. Delawares and other small vines may be set closer, although eight feet is preferable. When set, the vine is cut back to two or three buds. During the first year, the young canes are usually allowed to lie upon the ground at will, as seen in fig. 6. In the fall or winter, all the canes but one are cut off, and this one is cut back to two or three buds. The vine is, therefore, no larger at the expiration of a year's growth than it was when planted; but in the meantime the plant has become thoroughly established in the soil, and the second year's growth should be strong enough to form the basis for the permanent trunk or arm. If, however, the second year's growth is weak, it may be cut back as before, and the third season's growth used for the trunk. On the other hand, the growth of the first year is sometimes carried onto the wires to form the permanent trunk and arms, but it is only with extra strong vines in good soil that this practice is admissible. From this point, the treatment of the vine is discussed under training.
[Ill.u.s.tration: 6. A NEWLY SET VINEYARD.]
_When to Prune._--Grape vines may be pruned at any time during the winter. It is the practice among most grape-growers in the north to prune as time permits from November to late in February, or even early March. The sap flows very freely from cuts made in spring and early summer, causing the phenomenon known as ”bleeding,” or in Europe as ”weeping,” and in order to prevent this loss, pruning is stopped six weeks or more before the time at which the buds usually swell. It is yet a moot point if this bleeding injures the vine, but it is a safe practice to prune early. The vine is cut off an inch or two beyond the last bud which it is desired to leave, in order to avoid injury to the bud from the drying out of the end of the cane.
The pruning is done with small hand pruning-shears. The canes are often allowed to remain tied to the wires until the pruning is accomplished, although it is the practice with most growers who use the Kniffin system to cut the strings before pruning. The removal of the severed canes is known as ”stripping.” In large vineyards, the pruner sometimes leaves the stripping to boys or other cheap labor. The stripping may be done at any time after the pruning is performed until spring. It must be done before the growth starts on the remaining portions of the vine, however, to avoid injury to the young buds when tearing the vines off the trellis.
_Summer Pruning._--There is much discussion as to the advisability of summer pruning. It is essential to the understanding of the question that the grower bear in mind that this summer pruning is of two kinds--the removal or ”breaking out” of the superfluous shoots, and heading-in or ”stopping” the main canes to keep them within limits. The superfluous shoots are such as spring from small, weak buds or those which break from the old arms or trunk of the vine. Shoots which start from the very base of the old cane are usually weak and should be removed. Buds in this position are shown at _a a_, in fig. 4. The secondary or axillary branches, which often start from the base of the season's shoots, should be removed or broken out. These superfluous shoots are pulled off from time to time as they appear, or the buds may be rubbed off before the shoots begin to grow.
The heading-in of the main canes, while desirable for the purpose of keeping the vine within bounds, is apt to cause a growth of laterals which choke up the vine and which do not mature, and in those styles of training in which very little wood is allowed to grow, the practice may prevent the development of a sufficient amount of leaf surface to properly sustain the vine. Vines are often weakened by summer pruning.
These dangers can be overcome by careful attention, however, especially by heading-in very lightly and by doing it as late in the season as possible, when new lateral growth does not start readily. The necessity of much heading-in has been largely obviated in late years by the adoption of high or drooping systems of training, and by setting the vines far apart. The strong varieties, like Concord, Brighton and Niagara, should be set ten feet apart in the row, especially if grown upon the Kniffin system. Catawba, being a very upright grower and especially well adapted to upright training, may be set eight feet apart, and Delawares are often set as close as six or eight feet. It is doubtful, however, if any variety should be set less than eight feet apart for trellis culture. In Virginia and southward, where the growth is large because of the long seasons, vines are often set more than ten feet apart. In the South, the rows should run north and south, that the fruit may be shaded from midday sun. The only summer heading-in now generally recommended is the clipping of the tips when they fall over and begin to touch the ground. This clipping is often done with a sickle or sharp corn-cutter.
_Objects of Pruning._--The objects of pruning the grape, as of other fruits, are five:
1. To produce larger and better fruit.
2. To maintain or augment the vigor of the vine.
<script>