It’s time for winter-pruning wisteria. Here’s how a skilful twice-yearly pruning keeps them healthy and awash with blooms during their enchanting annual display.
Wisteria will flower if left unchecked, but flowering can be much improved when given a summer and winter-pruning. Apart from encouraging blooms pruning twice-yearly also helps to keep over-vigorous extension growth in check.
At this time of year, whilst the plant is dormant we cut right back to 2-3 buds to encourage the formation of buds and remove most of the old growth, allowing the new flower buds to hang unhindered by last year’s stems. Later, in August, we cut back extension growth to within about 15cm (6ins) of the main ‘framework’ of the wisteria.
One of the most common complaints we’re asked to look at are poorly flowering wisterias. If a wisteria has been regularly and properly pruned but still fails to flower then poorly conditioned soil might be the culprit.
Established plants will benefit from an annual application of fertiliser in spring, but they shouldn’t be overfed and the fertiliser must be well-balanced. A fertiliser which is high in nitrogen will encourage leafy growth at the expense of flowers, whereas using tomato food or a sulphate of potash is more likely to encourage flowering.
First and foremost wisterias need plenty of sunshine to grow and flower well, so they shouldn’t be planted on north or east-facing sites. Other than that, if possible, plant them where they are least likely to be confronted by dry conditions, vastly fluctuating temperatures and frost, as this can cause flower buds to drop in the spring.
Wisterias look gorgeous when trained against a house, however, they actually much prefer to grow free, so try simply planting one in your borders and watch it flourish as a standalone tree or loosely woven structure.
Wisteria in need of some TLC? Our garden maintenance team can work wonders. You can reach us here.