Jolly green giant: Euphorbias are the perfect plant for gardeners who never have enough time

Plants that can look after themselves are invaluable if you want to have a life as well as a garden – and euphorbias are just the ticket. Whichever you go for, they have a single stylish fact in common: almost all are green from root to flower, adding a monochromatic intensity to a garden colour scheme; and it's a hot look, according to those who have seen previews of this year's Chelsea Flower Show.

Unlike some other horticultural fusspots, euphorbias will manage almost anywhere you put them. But don't just restrict yourself to the obvious varieties which appear in every garden centre, because unusual species are often just as untaxing to grow. Euphorbia mellifera, for example, is a one-plant statement that will fill a tiny garden with a honeyed scent and tropical feel from its spreading foliage.

"I love euphorbias because they look after themselves," says Sue Wynn-Jones who, with her husband Bleddyn, runs Crûg Farm in north Wales, one of our most interesting nurseries supplying unusual plants. "We overlook Snowdonia, and the front of our house faces east, so it's very cold in winter, then baking in summer. Despite all that, Euphorbia characias characias looks absolutely fantastic."

Until 1991, the Wynn-Joneses were beef farmers, switching to plants in the troubled wake of BSE. They now spend up to three months a year abroad collecting seeds, and the Euphorbia sikkimensis they sell comes straight from the Lachem Valley in India. However, their plants are particularly vivid in hue, which may frustrate those looking to replicate this year's all-green tip. "How would you describe this colour?" Sue asks a co-worker in the potting shed. "Cherryade red," comes the reply.

The Wynn-Joneses' devotion to these plants is narrowly surpassed by Don Witton, the British collection holder for hardy euphorbias, who has 151 types growing on his Sheffield allotment. Next Sunday, he has his grand annual opening to the public: posters in the local shop ensure there is a good native crowd, but visitors have pitched up from as far away as South Africa and Japan. "Everyone knows Don's allotment," says Dot, his wife. "People have lunch in the pub then come to look round."

Some of the most scientifically significant euphorbias are under the care of Timothy Walker, head of the University of Oxford Botanic Garden. He is leading a programme to propagate one of the rarest of the genus, Euphorbia stygiana. Oxford's collection will look its best during the next month or so, and for £3 you can pop into the garden and check out another 150 types.

The University of Oxford Botanic Garden is hosting a special Euphorbia Day, (www.botanic-garden.ox.ac.uk) on Thursday; or you can see them on Saturday at Crûg Farm's Plant Fair (www.crug-farm.co.uk); and Sunday at Don Witton's open day in Harthill, Sheffield (www.euphorbias.co.uk)

Sit back and relax: Four that let you be lazy

Euphorbia mellifera

A vividly green giant that grows up to five foot high, with a gorgeous smell of honey (www.crocus.co.uk)

Euphorbia sikkimensis

Ruby buds in spring that turn to bronzey foliage with mustard flowers in summer (www.crug-farm.co.uk)

Euphorbia polychroma

Despite that deceiving Latin name, an all-green treat, from its deep emerald leaves to zingy lime bracts (www.penlanperennials.co.uk)

Euphorbia stygiana

One of the rarest of euphorbias in the wild, Chiltern gives gardeners the chance to grow it from seed (www.edirectory.co.uk/chilternseeds)