Wisteria Whether it’s clambering up a pergola, trained to a wall or draped over a garden arch, nothing beats wisteria for the stunning display of scented flowers that drip from its branches in late spring and early summer. To ensure an annual profusion of flowers you need to reach for the secateurs and give it a trim twice a year; the first in summer, followed by harder pruning when the plant is dormant in winter – here’s how.
Why prune
Wisteria will grow rampantly if left to its own devices, producing masses of leafy growth at the expense of the flowers - pruning 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.
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.
Summer pruning
Aim to prune plants during July or August. 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 shoots, leaving four to six leaves on each.
Winter pruning
Pruning 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.
Aftercare
Water plants well after pruning in summer and continue to keep soil damp until September. Drought at this time of year 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.