Pruning and Training Established Kiwifruit Vines
It is essential to maintain your kiwifruit vineyard well for optimum growth and productivity. Pruning probably is the most challenging aspect of vineyard maintenance.
Proper pruning is necessary for several reasons:
- To establish and maintain a well-formed permanent framework for the vine
- To obtain a balance between vegetative growth and fruit production
- To develop a canopy that uses available light efficiently (for photosynthesis), yet is open enough to obtain maximum fruit quality and flower bud formation for next year’s crop. An open canopy also facilitates harvest and reduces risk of fungal diseases such as botrytis.
All species of kiwifruit can be pruned in a similar manner. However, there are many different ways to prune a kiwivine. The following description covers the basic techniques. Grower experience may lead to modifications.
Dormant pruning of kiwivines is best done in late December to mid-February in the Pacific Northwest. Late-pruned vines may have excessive sap flow.
In kiwifruit, flowers are produced on current season shoots that grow from buds developed on 1-year-old canes (last year’s growth). Shoots that grow from older wood seldom produce fruit in their first season. Shoots from buds that were heavily shaded during the preceding season will be less productive than those from buds that were exposed to the sun.
Ideal 1-year-old canes have short internodes with well-formed buds, and stop growing early in the season. These canes develop early in the growing season. Fruiting laterals are current season’s shoots that have fruit on the basal nodes (4 to 6 buds); all the buds beyond the fruit are capable of producing flower buds for next year’s crop.
Male and female plants should be pruned differently when mature.
Female vines. When pruning a mature vine, remove about 70 percent of the wood that grew last season. Most of the wood removed is older wood that already has fruited. New fruiting canes usually will have developed at the base of last year’s canes. Figure 1 shows a typical fruiting cane that developed from the permanent cordon.
Figure 1. Kiwifruit Cordon in Production
Replacement fruiting canes that originate from the cordon may be left to replace older wood in the future. Fruiting canes should be separated by about 8 to 12 inches on the cordon. Head back replacement fruiting canes to force growth next season, and tie them to the wires for support. Do not tie canes too tightly or they’ll girdle during the growing season.
Spurs (shorter fruiting branches with short internodes) often originate from the older wood. Do not remove them unless absolutely necessary, as they are very fruitful (Figure 1).
Remove most of the older wood back nearly to the cordon. When necessary, you can leave some second-year canes for fruiting wood if 18 – 48 inches of new growth is present beyond where fruit was formed last season (Figure 2). Head back these fruiting laterals to 2 to 4 buds in fuzzy kiwifruit and 8 to 12 buds in hardy kiwifruit beyond where fruit was formed last year.
Figure 2. Dormant Kiwifruit Cordon
Take care that 1-, 2-, and sometimes 3-year-old fruiting canes are evenly distributed on the trellis to avoid overcrowding in any area of the canopy.
Remove twisted and tangled growth, shoots that cross from one side of the vine to the other, and wind- or winter-damaged shoots. Mature vines, spaced at 15 feet in the row, should have 30 to 45 fruiting canes per vine (spaced at 8 to 12 inches on both sides).
Male vines. The goal when pruning male vines is to produce as many flowers for pollination as possible, while keeping the vine manageable. One popular way to prune male vines is to cut most of the canes back to 6 to 12 inches as soon as flowering is finished. New growth during the summer will be sufficient to produce flowers for next year. If needed, you can trim the vine during the dormant season.
In New Zealand, summer pruning begins in mid-spring before flowers open. Remove shoots without flowers that originate outside of the wires (T-bar system). Cut back flowering laterals to four to six leaves beyond the last flower. Cut back watersprouts (vigorous shoots from older wood), and remove any tangles. During the summer, vegetative growth can be very vigorous. Remove shoots not wanted the following year for replacement canes and tip replacement canes to prevent tangling.
In California, more summer pruning is done on the pergola than the T-bar training system. However, take care not to excessively summer prune as fruit and sometimes canes may become sunburned.
Remove all suckers or shoots that grow from the trunk during the growing season.
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