Beautiful geraniums

When Somerset couple Rozanne and Donald Waterer discovered an unusual-looking seedling growing in their garden, they thought they had a rogue plant in their flower bed.

Now, 24 years later, the little geranium that the retired couple managed to cultivate is Plant of the Centenary. An intense violet blue, it’s been named ‘Rozanne’ after Mrs Waterer.

Thought to be a hybrid that occurred naturally in the Waterers’ garden, it’s a hardy variety capable of surviving frosts. When the Waterers first discovered it in 1989, they noticed it had much larger leaves than its neighbours and flowers that were twice as big.

In 1990 they found it flowered for six months. It was identified as a new variety by garden designer Adrian Bloom and was first seen at Chelsea in 2000.

The Royal Horticultural Society’s Lindley Library holds records of all the plants that have appeared at the Chelsea Flower Show since it started.

Fiona Davison, head of libraries at the society, says the plants short-listed for the Plant of the Centenary award reflect the garden fashions through the history of Chelsea. In the first decade of the show, rock garden plants were the rage.

More than 7,000 people voted online to select ‘Rozanne’ as the Plant of the Centenary. Unlike many geraniums, Rozanne has great heat tolerance, grows vigorously, but isn’t invasive.

It’s pretty happy in New Zealand in most soils and conditions, and should grow to around 40cm by 40cm.

But don’t limit yourself just to ‘Rozanne’. Geraniums are bright, beautiful, generous plants that flower for months on end. When they start to wane, a haircut and a decent feed brings them back to life.

They prefer an open, airy, sunny spot. The sun promotes enthusiastic flowering and helps to keep pests and diseases at bay. A container, therefore, is a good choice. The Mediterranean is littered with geraniums in (usually blue) pots and once you’ve seen a Greek courtyard or terrace full of them, you’ll be in love.

If you decide to go the container route, choose pots that are really well drained with several drainage holes rather than just one. Stick the pots on feet as added insurance

Don’t give them too much nitrogen-rich fertiliser or you’ll end up with great leaves and few flowers, but give them flower-promoting food from spring through until autumn.

If you live somewhere warm and wet (oh dear, that’s us), your geraniums will be more susceptible to disease.

The most common one is rust, which causes rust-like bumps on the leaves. Botrytis, or grey mould, can also spoil the flowers in lengthy periods of wet weather. The blooms grow grey beards (not unlike The Partner) and then turn brown and shrivel up. Pick off the dodgy flowers and spray the plants with a general purpose fungicide.

White fly can be a bother too. It’s attracted to certain types of geraniums in droves. You can spray it with pyrethrum-based sprays, or try growing feverfew and marigolds nearby.

Should you want to extend your geranium garden, it’s a very easy plant to propagate. Cut off pieces about 10cm long, plant into seed-raising mix, and you’ll have new plants in a few weeks.