Manual of American grape-growing

by U. P. Hedrick

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.

Pruning.

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.