During this hot weather period, our trees have been under stress. Due to the risk of falling branches, we ask you not to sit under or use benches under our trees or enter roped off areas.

September plant of the month - zonal pelargonium

Months of glorious colour from drought tolerant plants; what's not to like? Come down to Wisley and vote for your favourite in this year's People's Choice

There are some flowers that almost everyone knows, plants that remind us of childhood or hot, sunny holidays; that are such good performers, we grow them every year to fill our tubs or hanging baskets; and that we challenge ourselves to keep going over winter on a sunny windowsill.

There is one plant that plays all these roles – and that’s our plant of the month, the zonal pelargonium.

Pelargonium trial at WisleyUntil the first frosts arrive, we’re enjoying the last few weeks of the glorious colour they've been providing all summer. This year at Wisley we’re hosting a trial of both bedding and container-grown plants on the Trials Field and along the Hilltop road. It’s a beautiful sight, and as part of the People’s Choice we’re asking visitors to vote for their favourites. We’ll announce the results later in autumn. (On the Trials Field they’re hiding right at the bottom of the field near the Pavilion).

You say geranium...

Traditionally we know zonal pelargoniums as geraniums. But true geraniums are really quite different*. They look fabulous on their own, or as feature plants, and equally work beautifully teamed with petunias, begonias, fuchsias, lobelias, verbenas, nemesias and so on, to make colourful containers full of fun and flowers all summer.

So what is this plant? As a genus, Pelargonium has more than 200 shrubby or herbaceous species, mostly native to South Africa. The Zonal group are upright, bushy, succulent-stemmed perennials grown for their flowers or attractive foliage and we often use them as bedding and container plants.


PelargoniumChoices, choices

Their long-standing popularity means they’ve been subject to plant breeding for decades and now we have the pleasure of being able to choose from a range of single flowered (with five petals), semi-double-flowered (six to nine petals) and double flowered (more than nine petals) cultivars in numerous shades of pink, red, orange, lilac and white.

As long as we give them a warm, sunny, sheltered location many will tolerate drought conditions for short periods. Now that’s a great plant to use in bedding, containers, window-boxes and hanging baskets!

There’s so much interest in this plant that they have their own specialist group. The Pelargonium & Geranium Society was established in 2009 following the merger of The British Pelargonium and Geranium Society and the British and European Geranium Society. For more information visit: http://thepags.org.uk/

*Geranium or pelargonium?
A true geranium, or cranesbill, has five similar petals and ten stamens – they are radially symmetrical. A pelargonium has two upper petals, three lower ones – they are vertically symmetrical (click images to enlarge).
Geranium Rozanne

Click to enlarge: Geranium Rozanne
Pelargonium 'Magic Lantern'

Click to enlarge: Pelargonium 'Magic Lantern'


Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.