Hardy geraniums are among the easiest perennials to grow, producing masses of colourful flowers from late spring into summer. But once that first display is over, many varieties can start to look tired and untidy.
Rather than leaving them to flop across borders, giving them a good trim can completely rejuvenate the plant. Below, we share what to do with hardy geraniums once they've finished flowering.
1. Cut the whole plant back
Once the first flush of flowers has faded and the plant begins to look untidy, don't be afraid to give it a drastic trim.
'People are far too gentle with geraniums,' says Mirela Bajic, senior garden designer at House Designer. 'Once the first flowering is done and the whole thing has collapsed into a mess, cut it all to the ground – leaves, everything.'
Although it can seem harsh, hardy geraniums are remarkably resilient and respond well to a hard cutback. Use clean secateurs to remove all the old foliage, cutting the plant back to just above ground level. The variety 'Rozanne' responds especially well to this.
2. Water after cutting back
Once you've finished cutting the plant back, give it a thorough watering to help it recover and encourage fresh growth.
'It might look brutal, but water it and a couple of weeks later there will be a fresh mound of leaves and usually more flowers,' says Mirela.
As long as the plant is healthy and growing in suitable conditions, it should quickly produce a fresh flush of foliage, followed by a second display of blooms later in the season. During prolonged dry spells, continue watering occasionally while the new growth establishes – particularly if your geranium is growing in full sun.
3. Divide overcrowded plants
After flowering is also an ideal time to divide established hardy geraniums, if they've become congested or are producing fewer flowers.
'Every three to four years, lift the clump either in autumn or early spring, and use a sharp spade or garden forks to split the clump,' says Richard Barker, horticultural expert and commercial director of LBS Horticulture.
Dividing plants helps rejuvenate the original clump, encouraging healthier growth and better flowering in future seasons. It's also an easy way to create free new plants that can be replanted elsewhere in the garden or shared with friends and family.
4. Don't waste time deadheading individual stems
If your hardy geranium has become a tangled mound, removing stems one by one is unlikely to make much difference. ‘Picking at it stem by stem does nothing,’ explains Mirela.
Instead, save yourself time and give the entire plant a clean, even trim. It's quicker, encourages stronger regrowth, and helps restore geraniums’ lovely neat, rounded shape.
With one bold cutback and a good watering, hardy geraniums can quickly recover from their first flush, rewarding you with fresh foliage and a second display that lasts well into late summer.
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