Pruning an old wisteria vine
I inherited a very old, poorly trained wisteria vine with the recent purchase of a new house. I’d like to cut the wisteria back drastically and retrain it to a new support. How harshly can I prune the vine without killing it?
Cheryl Jennings Easterbrook, Redwood City, CA
Wisteria can stand up to brutal pruning. If you want to rejuvenate a vine, cut it completely back to the ground.
Photo/Illustration: Jennifer Blume
Lee Reich, Fine Gardening contributing editor and author of The Pruning Book, replies: Don’t worry about killing the vine, especially if you limit your drastic pruning to sometime between midwinter and midsummer, a period when the vine is still drawing on stored reserves rather than accumulating new ones for winter. With that caveat, you can prune wisteria to the ground and it will grow back. New growth following such drastic pruning will be very vigorous. One possible danger is that the vine will continue this vigorous growth for many years before settling down again to start flowering. So, it’s most important not to continue with the drastic pruning—one time is enough.
Once the wisteria starts to regrow, build a framework for the rejuvenated vine that consists of a trunk and one or more main arms. With the framework established, you can try pinching back the tips of all of the side shoots a few times during the summer. Go over each of these shoots again in winter, shortening them to two or three buds. This will keep the vine neater and more formal looking. If you’re lucky, the vine will begin to produce flowers in a year or two.
From Fine Gardening 80, pp. 74