Pruning wisteria

Nothing beats wisteria for the stunning display of scented flowers that drip from its branches in late spring and early summer, whether it’s clambering up a pergola, trained to a wall or draped over a garden arch.

Why prune wisteria?

Pruning wisteria carefully will bring forth a more spectacular display of flowers.

Wisteria will grow rampantly if left to its own devices, producing masses of leafy growth at the expense of the flowers – pruning wisteria diverts the plant's energy from making foliage into producing flower buds, while reducing the mass of whippy shoots will help light reach the network of branches inside.

Pruning wisteria

Although some wisterias cover a large area, such as the front of a house, resist the temptation to trim it back quickly with a pair of shears or hedge trimmer. Precise pruning with secateurs will result in a better show of flowers.

Step 1: summer

Wisteria should be pruned twice a year –  aim to prune the young green wisteria shoots during July or August. This is to keep the size in check and allow more light to reach the plant. 

Start by tying in any strong side shoots to fill gaps on supports or use to replace older branches. Tie young growth loosely to these branches, which are best removed in winter – the new growth can then take its place on the support system. 

Cut back all the remaining young shoots, leaving four to six leaves on each.

Step 2: winter

Pruning wisteria in February or March is much easier as you can see the structure of the plant much better after the foliage has fallen. 

Simply reduce each of the shoots you pruned in summer back to two buds. Winter pruning keeps the plant tidy and ensures the flowers are not obscured by leaves.

Aftercare

After pruning wisteria, water it well in summer and continue to keep soil damp until September. 

Drought can result in a poor floral display in a few months' time as flower buds form in late summer. Dry soil may result in buds and flowers dropping early.