Pruning wisteria can be daunting prospect but it’s not as tricky as you might think. Pruning is essential for wisteria, not only to keep the plant’s growth in check but also to keep it flowering abundantly.
Wisteria is a vigorous plant that will produce lots of long, whippy shoots, which, if left uncontrolled, can dislodge roof tiles, clog gutters and creep into attics. Even worse, they won’t produce any flowers.
If you follow a strict regime for wisteria pruning twice a year, you will be rewarded with showy pendant racemes of fragrant flowers.
Read our in-depth guide to growing wisteria, including 20 stunning varieties to grow.
Pruning wisteria
When to prune wisteria
Wisteria needs to be pruned twice a year, in winter (January or February) and summer (July or August). Pruning in winter keeps it tidy for the season ahead and means that the flowers will not be hidden by the leaves. Pruning wisteria in summer controls the plant’s size and ensures that it will produce plenty of flower buds.
How to prune wisteria
Pruning wisteria in summer
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- Tie in any stems that are needed to fill in gaps against the wall, or to extend the plant over a pergola.
- Cut back all the rest to about 30cm from the point from which they have grown. Some gardeners leave this job until the following spring, but doing it now not only makes wisteria look neater, it also lets the sun into the plant to ripen the young stems. This is important for future flower-bud production.
Pruning wisteria in winter
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- The following January or February, shorten the stems that you pruned in the summer to about 5cm from the old wood. Doing this will create short, stumpy shoots known as spurs.
- If you look closely at these spurs there are usually two sizes of bud: short, thin ones and fat, plump ones. The plump ones are the flower buds; the thin ones will produce more shoots. More long shoots will have grown since the summer. Prune these back to four or five buds from the main stem, making the cut just after a bud.
How to prune an overgrown wisteria
February is also the best time to prune an overgrown wisteria. You can remove branches that are growing away from the wall or over a window or remove old, woody branches from mature plants. Saw these off just above a young, vigorous branch or shoot. If the branch is very long, remove it in sections. Aim for a framework of well spaced branches; you may need to train in new growth during the summer to fill in any gaps.