How to Prune Wisteria Plants & Trees

Japanese wisteria requires annual pruning.

Both Chinese wisteria and Japanese wisteria are common garden favorites. Growing wisteria is a fairly straightforward process. Healthy, vigorous wisteria requires well-drained soil, a sunny location and annual summer pruning. How you should prune your wisteria may depend partially on what you want to achieve with pruning. According to Aggie Horticulture, common goals for pruning include training, health maintenance, improved quality, increased flowering and restricting growth.

Things You'll Need

• Pruning shears
• Lopping shears

Instructions

1. Use heavy-duty pruning shears to trim away dead, broken or otherwise damaged branches at the point of origin or at least back to a point where the branch is still healthy. If the vines you cut are more than 1/2 inch in diameter, use lopping shears instead of pruning shears.

2. Find one strong main branch to attach to the arbor and trim away all offshoots of this branch between the ground and the arbor or trellis the wisteria will be trained to climb. Cut undesired side shoots after the sixth leaf.

3. Cut branches that interfere with the growth of other branches. These cuts should be made at the point of origin from the main stem.

4. Cut old stems that are declining in health -- but are otherwise undamaged -- back by about one-third of their full length.

5. Prune the top of the wisteria plant in July to promote vigorous flowering. Many gardeners mistakenly prune wisteria during the dormant season. This results in heavy vegetation and a lack of flowers.

Tips & Warnings

• Make angled cuts rather than straight horizontal cuts. Slanted cuts tend to heal faster.

• Overpruning may not kill your wisteria, but it is likely to reduce its overall health and beauty.

References

• Aggie Horticulture: Follow Proper Pruning Techniques
• Ohio State University Extension Fact Sheet: Growing Wisteria
• Purdue Extension: Wisteria a Mystery for Most Gardeners