Pruning and Training
Like most perennial fruit plants, they require dormant pruning; however, they also need to be pruned several times during the summer by cutting back the terminal growth to four to six leaves beyond the last flower. Also remove watersprouts (vigorous shoots originating from older wood) and shoots from the trunk, as well as vines that become entangled. This removal may be substantial during the summer.
Dormant pruning should be done sometime from December to March in Pennsylvania. On this species, flowers develop on current-season shoots that come from 1-year-old canes (last year's growth); shoots from older wood rarely produce flowers. As with grapes, a large percentage of the wood--as much as 70 percent--will be removed. New fruiting canes will have developed at the base of last year's growth (Figure 12.1). Replacement canes are left for future fruiting, and fruiting canes should be spaced between 8 and 12 inches on the cordons (permanent horizontal branches).
Training should begin in the first year of planting. Like grapes, these flexible vines can be trained to a number of forms; although in commercial plantings, a pergola (Figure 12.2) is the most common training system since it accommodates the kiwi's high level of vigor. Also, like grapes, establishing the trunks and structure of the vine early in its development will ensure fruit production for many years to come. Figure 12.3 shows a typical hardy kiwi plant training system over the first 2 years of its life. For additional options, see the training systems in Grapes.
Figure 12.3 The First two years of training a kiwi vine (courtesy of Oregon State University)
(A) Prune to two buds at planting.
(B) Train one shoot as trunk, remove all others (growing season, year 1).
(C) Head back trunk as shoot growth at terminal loses vigor (growing season, year 1).
(D) Continue to remove lateral shoots, let trunk grow beyond wire, then head to just below top wire (growing season, year 1).
(E) Choose two shoots to form cordons (lateral trunks). Head back to 1/4 inch diameter in dormant season (growing season, year 1).
(F) Shoot growth, year 2. Pruning cuts in dormant season of year 2 also are shown by /