How to Trim Wisteria Vines

Trim dead or broken branches from the wisteria vine at any time, whether in the dormant winter season or when the plant is growing. Prune the limb by making a cut into lower healthy vine tissue. Make the cut 1/2 inch above a lower bud, leaf or branch.

Remove any errant vines that pose a safety hazard or could damage property, such as vines blocking a sidewalk or window view, or vines growing under a house shutter or onto a telephone wire. Clip the problematic vine stem back to its point of origin on a lower main vine. Make the cut flush or no more than 1/4 inch above the stem's attachment to the lower vine.

Tidy an overgrown or shaggy-looking wisteria vine in mid to late summer by reducing vine lengths. Any new growth shoots that are undesired or excessive to the overall silhouette of the wisteria may be cut back. Cut these unnecessary vines back to no more than 6 inches long. Keep four to six leaves on the shoots, so the plant can still photosynthesize light the rest of the year. Removing too much of the vine can stunt growth and limit the accumulation of carbohydrates in the roots. Food reserves in roots allow the wisteria to survive the winter and grow again in spring.

Wait to prune or remove vigorous, healthy vines -- those that form the plant's primary size, structure and silhouette -- until late winter. That's when annual pruning maintenance should be done, which involves cutting back branches harshly to a simple framework.