Plant Doctor Archive

Shaping abutilons

I HAVE abutilons on the south side of my house and have been pruning them into standards. I cut them back to the main stem every year, but they grow so much they become top heavy. When we get strong winds, they blow over, even though they're staked. If I prune them to keep them in shape, this cuts the flowers off. Is there any other way I can keep them in shape or do I have to forego flowers for a while?

UNFORTUNATELY, abutilons are not the easiest plants to train into standards. Like their cousins, the hibiscus, they flower on new growth, so if you cut them back severely you get no flowers for a while.

One of their great points, however, is they can flower right through winter, so my personal preference would be to try to have them flowering then and I'd be willing to forego early summer flowers when there is a lot of other colour in the garden. I'd tend towards pruning them in spring.

Even then, it's quite likely they'd put on so much growth they'd still be prone to blowing over, so make sure they have a really strong wooden stake for support. Every now and then over summer selectively cut back some shoots quite hard to restrict size, but not enough to spoil the flowering effect.

Depending on your conditions, you may even be able to get away with this type of selective pruning all year and not have to cut the plant back at all in spring.

A point worth bearing in mind with plants of this kind is the shoots you cut back in summer tend not to grow away as strongly as those cut back in early spring and they're likely to flower sooner. Also, try to avoid encouraging strong growth - don't fertilise unless the plants look really deficient and even then use a high potassium feed rather than high nitrogen. Don't water them unless absolutely necessary.

You could also try taking a spade to the root system every now and then, pushing it down as far as possible, 60cm or so out from the trunk, to chop through some roots. That should slow them down a bit.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.