Manual of American grape-growing

by U. P. Hedrick

[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.

Double-headed vines.

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.