Training Young Kiwifruit Vines
Proper pruning during the establishment years is necessary to establish a well-formed permanent framework for the vine. Developing or training young kiwifruit vines into a bilateral cordon allows for easier management when the plants are mature. Kiwifruit produce a crop on shoots (fruiting laterals) that grow from 1-year-old canes (last year’s growth). In the first few years, you train vines the same way for both the pergola and the T-bar system.
Prune dormant kiwivines in late December to mid-February in the Pacific Northwest. Later pruning may cause excessive sap flow.
First growing season
The main objective during the planting year is to develop a single, straight trunk. At planting, prune plants back to one or two buds (above the graft union in grafted plants) (Figure 1-A).
Once shoots start to grow, select one vigorous shoot to train upward as the trunk. Place a stake beside the shoot to facilitate training. String from the wire to the stake can add support as well. Tie the shoot to the stake (not too tight or you’ll girdle the shoot) at frequent intervals to help prevent breakage.
Do not allow the shoot to wrap around the stake. Concentrate growth into this shoot by removing suckers at the base of the vine (Figure 1-B).
Remove all basal lateral shoots that break along the trunk. If the main shoot loses vigor and begins to twist slightly, top the shoot and train up the strong new “leader” (Figure 1-C). Continue to train the trunk until it’s 2 to 3 inches above the wire (Figure 1-D).
Figure 1. Training a Young Kiwifruit Vine
If the shoot reaches the wire early in the season, you may try to form the cordons in the first year. To do so, top the shoot to about 4 inches below the training wire to encourage lateral branch formation. This forms a nice “Y” for the cordons. Select two shoots, growing in opposite directions, and train them along the center wire to form the two main arms called cordons (Figure 1-E).
Another option is to train the trunk up one way along the wire and wait until the next season to train a shoot the other way. This results in cordons of unequal age which may make management more difficult.
During the first dormant season, head back the cordon(s) to wood of 1/4 inch in diameter or larger (Figure 1-E). If vines did not have adequate growth to form cordons the first season, head the trunk back about 2 inches below the trellis wire to force new buds early the next season.
The objective in this season is to develop two permanent cordons from two strong shoots growing in opposite directions from the trunk along the center wire. As each cordon grows, hang it over the wire and wrap it every 18 to 24 inches to ensure that it’s securely attached to the wire.
Retain lateral branches that are produced along the cordons at about 8- to 12-inch intervals (Figure 1-F). Carefully tie these canes to the outer trellis wires. Remove all others by summer pruning before they twist around the shoots you want to keep.
In the dormant season, prune the main cordons and the retained lateral canes back to wood 1/4 inch in diameter or larger (Figure 1-F). The first crop will form on shoots from these canes in the third year. Pruning the canes during the dormant season encourages fruiting the following year. Remove any suckers and new growth on the trunk (Figure 2).
Figure 2. Kiwifruit Vine in Third Growing Season
Continue to extend the cordons, if necessary, by training the strongest shoots down the center wire until they’re within about 1 foot of the cordon of adjacent vines. Do not allow them to twist tightly around the wire, because this may restrict sap flow later.
Continue to train lateral branches perpendicular to the cordons (Figure 4). Do not train shoots along the outer wires parallel to the cordon; they will cause too much competition for light.
In the third year, concentrate on developing the vine’s framework. Fruit will form on shoots produced on last year’s growth (Figure 4). Fruit in the third year may sunburn due to inadequate canopy cover. Do not overcrop the vine. It may be a good idea to remove some of the fruit to divert more energy into vegetative growth.
In the third dormant period, prune so that 15 to 20 well-spaced latereral canes remain on the vine, depending on vigor. Remove any suckers or side growth on the trunk.
The permanent vine structure should be established by the fourth year. Future pruning will renew fruiting canes and maintain the vine framework and crop load. See Pruning and Training Established Kiwifruit Vines for diagrams/descriptions of pruning producing vines.
Training of vines to a T-bar and pergola system is similar. In a pergola, the vines are grown as straight, single trunks until they reach the top of the structure. A single strong permanent leader (cordon) then is allowed to grow in each direction along the main wire.
To form the canopy of a pergola, develop a system of fruiting canes from the cordons at right angles to the wires. Fruiting canes can be retained longer on pergolas and may be more permanent than on T-bars. Fruiting laterals or shoots develop on the fruiting arms. It takes up to 7 years to develop a full canopy in a pergola.
Bernadine C. Strik, Extension Berry Crops Specialist, Oregon State University.
This fact sheet is adapted from Oregon State University Extension Publication EC1464, Growing Kiwifruit, which can be purchased from the Department of Extension & Experiment Station Communications. How to Order