Gardeners with wisteria in their outdoor spaces are being urged to complete a simple pruning job by the end of this week to avoid wild growth. The task involves cutting the plant's side shoots back by around 20cm, or five leaves, with mid-August listed as the opportune time.
Why prune wisteria in summer?
According to the Royal Horticultural Society (RHS), summer pruning helps control the plant's size and can stop it growing into places like gutters and windows. The RHS advises cutting the whippy green shoots produced during the year after flowering.
Greenhouse Stores lists mid-August as the ideal time for this task, placing wisteria pruning among its priority jobs for the third week of August, which runs from August 15 to 21. That makes this week, August 17 to 21, a timely window for gardeners who have yet to tackle the task.
How to prune and what to expect
For gardeners tackling the job, the process is straightforward: identify the long, flexible shoots produced this year and shorten them back towards the main branch. The RHS says this reduces excess vegetative growth, encouraging the development of shorter flowering spurts and improving the chances of flower bud formation for future displays.
The plant's vigorous nature is precisely why regular pruning is recommended. The RHS describes wisteria as a vigorous climber and says establishing a twice-yearly pruning routine can help keep it under control while encouraging better flowering.
Complete the routine in winter
Gardeners should also know that the summer cut is only half of the routine. The RHS recommends returning to the plant in January or February, when the wisteria is dormant, and shortening the shoots further to two or three buds.
The RHS also includes wisteria pruning among its August gardening jobs, advising that it should be done after flowering. Its guidance notes that removing summer growth improves air circulation and sunlight reaching younger growth, while helping restrict unwanted vegetative growth.
For anyone whose wisteria has started sending long shoots across walls, windows or other parts of the garden, now is therefore a good time to get the secateurs out. Keeping on top of the summer growth can help prevent the climber from becoming difficult to manage and set it up for the next stage of its pruning routine.
