Pruning Lavatera: how and when do you do it?
The Lavatera , or shrub mallow, is a real treat for your summer garden. It blooms profusely for months with large, open flowers in white, pink, or even deep red. But to keep the plant in shape and flowering, you need to prune it annually. We explain the best way to prune Lavatera – and why the name Lavatera is actually a mistake.
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Although gardeners and nurseries still frequently use the name Lavatera , it's no longer botanically correct. Most species in the Lavatera genus are now officially called Malva . However, we're gardeners, not botanists, and in practice, the distinction between the two is quite useful:
- Mallows are usually herbaceous, low plants (like the well-known cheese herb) that flower in summer.
- Lavateras are usually more shrubby plants that quickly grow into bushes of up to two metres high and flower from summer to autumn.
These shrubs are also known as shrub mallow (such as the popular Lavatera × clementii 'Barnsley' , see photo). The shrub mallow is what we're discussing in this article.
Lavatera , or shrubby mallow, grows quickly and can quickly become untidy or top-heavy if left unpruned. The plant blooms on young wood, so regular pruning ensures it blooms more profusely. Pruning also prevents it from becoming bare at the bottom. If you don't prune shrubby mallow, it becomes increasingly woody at the bottom. And because it blooms on new wood, you won't get any flowers at the bottom – much like many hydrangeas or butterfly bushes .
The best time to prune Lavatera is early spring, between late March and mid-April. Wait to prune until the worst of the winter weather has passed, as pruning wounds are susceptible to frost damage . In summer, it's best to just deadhead the spent flowers and, at most, lightly prune the shape. But be careful: if you prune too heavily in summer, the shrub will bloom less enthusiastically.
Pruning Lavatera is very simple, and you can't really go wrong. Here's how:
Prune Lavatera or plum alva in early spring, preferably between late March and mid-April. Wait until the worst of the frost has passed. If you prune too early, the pruning wounds may be damaged by frost. This will make it harder for it to re-grow.
Cut all branches back to about 15 to 30 centimeters above the ground. You want to leave at least one or two healthy buds on each branch. The plant will sprout new growth from these. The older and more woody the plant, the deeper you can generally prune. Also remove dead wood, damaged branches, and crossing branches immediately.
After pruning, give the plant some organic fertilizer or compost. Lavatera responds to pruning by growing vigorously, and new shoots will appear before you know it. Give the shrubby mallow a sunny, well-drained location. You can prune lightly in the summer to maintain its shape.
Regularly remove faded flowers so the plant doesn't waste energy on setting seeds. This allows it to focus entirely on producing new flowers. Deadheading can be done throughout the entire flowering season and will keep them blooming until autumn.
In autumn, it's best to halve the long branches of the shrub mallow. By making the shrub a little lighter for the winter, it will be less susceptible to storms and strong winds that could loosen and damage the roots.
In severe frost, your shrub mallow can freeze, but after a thorough pruning in the spring, Lavatera will usually recover well – ready for a new flowering season.
"Pruning makes flowers bloom" is a famous saying for a reason. But how do you go about it? In this special edition of Gardeners' World magazine, we've laid it all out for you. When, how, and why exactly do you prune? Including an annual pruning planner, you can never go wrong again. Here's to a blooming garden!
