Gardeners who have one striking climbing plant in their outdoor areas have been given a straightforward and uncomplicated task to add to this week's agenda. The timing is crucial, and they're being advised to make sure it's done by the end of this week to prevent uncontrollable growth.

The plant concerned is wisteria, and horticultural advice suggests trimming its lateral shoots as part of summer upkeep. Greenhouse Stores identifies mid-August as the ideal moment to reduce the shoots by approximately 20cm, or five leaves.

According to the Royal Horticultural Society (RHS), summer trimming helps manage the plant's dimensions, and can prevent it from spreading into areas such as guttering and window frames. It recommends cutting the flexible green shoots that emerge during the year following flowering.

For gardeners undertaking this hassle-free task this week, the procedure is fairly simple: locate the long, pliable shoots grown this year, and cut them back towards the primary branch. There's more to the job than simply making an unruly plant appear neater, with the RHS stating it minimises excessive leafy growth, thereby promoting the development of shorter flowering spurs and enhancing the likelihood of flower bud formation for subsequent displays.

The plant's energetic character is exactly why regular trimming is advised. The RHS characterises wisteria as a vigorous climber and states that establishing a twice-yearly pruning schedule can help maintain it while encouraging superior flowering.

Close-up, Selective Focus View of Purple Wisteria Flowers Blooming [Close-up, Selective Focus View of Purple Wisteria Flowers Blooming]
Wisteria are classed as climbing plants

Gardeners should also be aware that the summer trim is only part of the process. The RHS advises returning to the plant in January or February, when the wisteria is dormant, and cutting the shoots back further to two or three buds.

Greenhouse Stores lists wisteria pruning amongst its key tasks for the third week of August, which falls between August 15 and 21. This makes the current week, August 17 to 21, an ideal opportunity for gardeners who are yet to address the job.

The RHS also includes wisteria pruning amongst its August gardening tasks, recommending it be carried out after flowering. Its guidance highlights that removing summer growth enhances air circulation and allows more sunlight to reach younger growth, while helping to curb unwanted vegetative spread.

For those whose wisteria has begun sending lengthy shoots across walls, windows or other areas of the garden, now is therefore an opportune moment to reach for the secateurs. Staying on top of summer growth can help prevent the climber from becoming unruly and prepare it for the next stage of its pruning schedule.