How to Prune Wisteria

When it blooms, the vigorous wisteria vine is spectacular. But it doesn't always perform on cue. You can find all kinds of wisdom out there, but to my mind, the key is pruning. Once you've figured that out, you'll be rewarded in spring. In The Pruning Book (The Taunton Press), Lee Reich recommends a combination of summer and winter pruning of side shoots. In midsummer, prune each side shoot to about 6 inches long. This will trigger growth of new shoots. Go over each of these branches again in late winter and shorten them to two or three buds.

In other words, identify a few primary branches. For instance, if you want to train the vine over an arch or along the edge of a porch, pick one vine. Then, edit all the redundant vines. It might seem harsh, but this vine is vigorous and will push you around if you don't assert yourself. After you've identified the primary branches, you can begin pruning the side shoots: once in midsummer; once in winter. The idea is to create lots of short spurs all along the main vines. Again, be assertive.