The Isabella grape is hardy and productive in western New York. In 1856, we noticed a vine that had been laid down in a dry place and covered slightly with earth, in autumn; the fruit was more abundant, and one fourth larger, than that on a similar vine by its side that had remained on the trellis during winter: this shows the value of protection even to hardy vines.
Training.—There are many methods, and the question of preference depends upon the location of the vines, the space they may occupy, and the taste of the cultivator. There are four principal systems—the cane or renewal system, spur system, fan-training, and spiral or hoop training.
The renewal system we prefer for trellises. Put posts firmly in the ground eight feet apart, allowing them to be seven feet above ground after they are set; put slats of wood or wire across these, a foot apart, commencing a foot above the ground. Set vines eight feet apart; let the vines be composed of two branches, coming out near the ground: these can be formed by cutting off a young vine near the ground, and training two of the shoots that will spring from the bottom. These two vines should be bent down in opposite directions, and tied horizontally to the lower slat of the trellis; cut these off, so as to have them meet similar vines from the next root; upright shoots from these will extend to the top of the trellis, and it is then covered, and the work is complete. After these upright canes have borne, cut off every alternate one, two or three inches from its base, and train up the strongest shoot for a bearer next year: thus cut off and train new alternate ones every year, and the vine will be constantly renewing, and be in the most productive state; keep the vines clipped at the top of the trellis, and the sap will mature strong buds for next year's fruit. We regard this the most effectual of all training. The principle of renewal can be applied to any form of vine, and eminently promotes fruitfulness. Many complain that their vines, though liberally pruned, do not bear well. The difficulty may be that the new wood is principally removed, while the old is left to throw out strong-growing shoots, bearing abundance of foliage and little fruit. More of the old wood removed, and more of the young saved, would have produced less vines and much more fruit.
Pruning—is the most important part of successful grape-culture. Mistakes on this subject are very injurious. Let vines grow in their own way, and you will have much wood and foliage, and very little, poor fruit. Some cut off the shoots in summer just above the fruit, and remove most of the leaves around it to expose the fruit to the sun. This often proves to be a ruinous mistake; the sap ascends to the leaves, and there amalgamates with what they absorb from the atmosphere, and thus forms food for the vine and fruit. It is the leaves, and not the fruit, which need the sun: the leaves are the lungs, upon the action of which the life and health of the fruit depend. Blight of the leaves destroys the fruit, and a frequent repetition of it destroys the vine. Grape-vines should not be pruned at all until three years old, as it retards the growth of the roots, and thus weakens the vines. Older vines should be freely pruned in November or December; pruned in winter they may bleed in the spring, and pruned in the spring they certainly will bleed. Tender vines, not protected, may have an excess of wood left in the fall to allow for what may perish in winter; in this case, cut away the dead and surplus wood in spring, but never until the leaves are well developed, so as to prevent bleeding. Necessary summer-pruning is of much importance. Remove no leaves, except the ends of branches, that have already made as much wood as they can mature. In the Middle states this should be done about the last of July, and at the South a month earlier. Weak lateral branches, that bear no fruit, may be removed, but not all of them, for it is on the wood of this year's growth that the fruit will be found the following season. Old wood does not send out wood in spring that will bear fruit the same season; that wood will bear fruit next season if allowed to remain. Whoever observes will notice that grapes grow on young shoots of the same season; but they are shoots from wood of the previous year's growth, and not from old wood. Many suppose if they trim their vines very closely, as the old vines send forth abundance of new wood, and it is new wood on which the fruit grows, of course they will have abundance of grapes; and they are disappointed by a failure. The explanation of the whole is, fruit grows on new wood, from wood of previous year's growth, and not from old vines; hence, in lessening a vine, remove old wood. This is the renewal system, whatever the form of the vine, and is the whole secret of successful pruning. This accounts for the great success of the Germans in producing such quantities of grapes on low vines. In their best vineyards, they do not allow their vines to grow more than six or seven feet high, and yet they produce abundantly for many years. They so prune as to have plenty of last year's wood for the production of fruit the current season; after this has borne fruit, they remove it to make room for the young wood that will produce the next season. This principle is applicable to vines of any shape or size you may choose to form. The removal, in summer, of excessive growth, and shortening the ends of those you design to retain, throws the strength of the vine into the fruit, and to perfect the wood already formed. Liberal fall-pruning is necessary to induce the formation of new wood the next season, for bearing the following year. Parts that grow late do not mature sufficiently to bear fruit the next season; hence, cut off the ends in summer, and let what remains have the benefit of all the sap.
Reduction of Fruit.—The grape is disposed to excessive bearing, which weakens the vine, and injures the quality of the fruit. Liberal pruning in autumn does much to remedy this evil, by not leaving room for an excessive amount of fruit: hence, when you have a plenty of fruit-bearing wood, cut off the ends, so as to leave spurs with two buds, or at the most only four; when too much fruit sets, remove it very early, before the juices of the vine have been wasted upon it. A vine cut or wounded in spring will bleed profusely. Sheet India-rubber, or two or three thicknesses of a bladder, wet and bound closely around, may prevent the bleeding.
Mildew—is very destructive in confined locations, without a good circulation of air. Sulphur and quicklime, separate or combined, dug into the soil around the vines, is a preventive. Straw or litter of any kind, spread thick under the vines, is, perhaps, the best remedy—the action of it is in every way beneficial.
Insects.—The rosebug, spanworm, great greenworm, and many other insects, infest grapevines, and do much injury. The large worms are most easily destroyed by hand; the small insects by flour-of-sulphur, or by snuff, sprinkled over profusely when the vines are wet. The various applications recommended in this work for the destruction of insects, are useful on the grapevine. The principle is to apply something offensive to the insects, without being injurious to the vines.
Preserving Grapes.—Packed in sawdust or wheat-bran, always thoroughly dried by heat, they will keep well until spring. Another method is packing them in cotton-batting or wadding (the latter is best); or put them in baskets holding no more than four or five quarts, cover tight with cotton, and hang up in a cool, airy place, and they will long remain in good condition. In shallow boxes, six inches deep, put a sheet of wadding, and on it a layer of bunches of grapes, not allowed to touch each other; on the top of the grapes put another sheet of cotton, and then another layer of grapes, and so the third, covering the last with cotton, and put the cover on tight, and keep in a cool place. This is the most successful method.
A new method is to suspend hoops by three cords, like a baby-jumper, and hang the bunches of grapes all around it, as near as possible without touching, on little wire hooks, passing through the lower ends of the clusters, allowing the stem end to be suspended, and the grapes hang away from each other, and if the place be not damp enough to mould them, and not dry enough to cause them to shrivel, they keep exceedingly well. It requires more care and judgment, than the other methods. A very cool situation, without freezing, is essential in all cases. It is also necessary to remove all broken or immature grapes, from the clusters you would preserve.
Varieties are very numerous, and their nomenclature is confused, as that of other fruits. It is utterly useless to cultivate foreign grapes in the open air in this country. They succeed very imperfectly, even in the Southern states. But for cultivation under glass, they are preferable to any of our own. The following foreign grapes are preferred in this country:—