Lavender: The key gardening task to remember this month or risk ending up with ‘woody and leggy plants’

According to Monty Don, this is why lavender needs trimming in August, as leaving the task too late could lead to “woody, leggy plants".

The horticulturist explained: “The best time to do this is as soon as the flowers start to fade, which, depending on the variety, can be any time between midsummer and the end of August.

“But do not wait for the seed heads to form or the flowers to turn brown as you want to allow the maximum amount of time for regrowth before winter.”

Gardeners also have the option of trimming their Lavender in April, but should note that this could slightly delay flowering.

Using secateurs, prune your lavender by cutting back the whole plant by 2.5 to 5 centimetres (or one to two inches).

The plants will thrive if pruned back thoroughly but gardeners are advised not to cut into old wood, as lavender won’t re-grow from this.

Instead, they should ensure there is some healthy green growth left for the plant to regenerate from.

“Cut back hard to a good compact shape but be sure to leave some new shoots on each stem - lavender will often not regrow from bare wood,” shared Monty.

“These new shoots will grow fast and provide an attractive and healthy cover to protect the plant in winter and provide the basis of next year’s display.”

Other plants to trim in August:

Once your lavender has been pruned, Monty Don recommends giving any hedges a trim for slower regrowth. He explained pruning in winter, conversely, leads to rapid and vigorous growth spurts.

Monty Don said: “It is safe now to trim hedges in the knowledge that the vast majority of nesting birds have fledged.

“Summer pruning results in slower, less vigorous regrowth than a winter trim so clip hedges to their height and shape that you wish them to remain for the rest of the year.”

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Trimming hedges is a relatively straightforward task, but applying the following strategy could make the job easier.

“Start with the sides, making sure that you have a slight ‘batter’ or outward slope from the top to the bottom,” said Monty.

“This ensures that the lower section is not shaded by the top growth - which is always more busy as it gets more light - and the hedge remains fully ‘furnished’ right down to the ground.”

“Deciduous hedge trimmings can be mown and added to the compost heap and evergreen ones taken to the council green waste.“