Gardening: Flowering tearjerker

Alliums - decorative onions - are splendid plants for the border, writes Kirsty Fergusson, but be sure to hide their ugly ankles

Decorative onions ("alliums" sounds so much better) are no strangers to the summer bulb catalogue. But it is curious that such handsome and easy-to-grow plants are seldom seen outside the photogenic gardens of the horticultural intelligentsia.

Summer-flowering bulbs have to shout pretty hard at this time of year. But most people who get round to thinking about alliums are put off by the foliage, which starts to look hideous even before the flowers have got going properly. You wouldn't enter an allium into a Beautiful Ankles competition. But the good news is that the flowers rise on long stems above the mess below. If you combine alliums with other plants that will hide the ugly leaves, this will allow the star-burst globes of purple, magenta or cream to float above a borrowed skirt of foliage.

I noticed this at the Chelsea Flower Show this week, in Fiona Lawrenson's Chapel Garden for BSkyB, where the white orbs of allium 'Mount Everest' rose above the fat, glossy leaves of zantedeschia 'Green Goddess' surrounded by a fluffy tutu of Tiarella grandiflora and white dicentras. And I have a clear memory of a previous Chelsea display where great thistly silver leaves of onopordum masked the origins of the gloves of A giganteum that hung above them like purple moons. That was a simple idea which worked well - provided you're happy to have 6-ft plants at the front of the border later on in the summer. (Why not? It might be fun to have some of the giants at the front for a change, rather than stuffed away at the back.)

Alliums are well suited to dry conditions and are much used by advocates of natural gardening, in association with silver-leaved shrubs, grasses, sages, poppies and other cornfield annuals. Allium spaerocephalon is an excellent candidate for this kind of looser, less structured planting: its flower heads are smaller than the great globes of the better known A giganteum or A christophii and more egg-shaped than round, in the deepest shade of magenta possible. Imagine them as they are at the celebrated Westpark in Munich, dancing above a sea of lavender-blue sages, nepeta, feathery bluish-green Stipa calamagrostis with a scattering of moon daisies, poppies and corncockles.

In Beth Chatto's gravel garden you will find the rather shorter, stouter Allium christophii hiding its ankles in the deeply purple fringes of Sedum maximum 'Atropurpureum' and rubbing shoulders with a pale mauve tulbaghia and a mustard-flowered helichrysum. Fluffy stipas echo the pinky-beige stage of the alliums on the turn at the end of a dry summer.

In the wilder parts of my own (Dorset) garden, as well as our local roadside banks, I have been completely nonplussed by the way that nature has pulled off a master-stroke in the integration of alliums. In May the air is pungent with the scent of wild garlic, Allium ursinum, known around here as ramsons; the plants naturally mingle with bluebells - not at all usual in the wild - as well as yellow celandines, pink campion and the vivid green of young ferns uncurling on long stems. For two weeks in May, driving around the lanes is like taking a trip through a double herbaceous border. And then, for a day or two, the garlic leaves are noticeably awful - until the big umbellifers take over and cover up the rotting leaves. Nobody in their right mind would plant the incredibly invasive wild garlic in a border, but I should think that a strategically placed angelica would work to the same effect as the roadside umbellifers.

From midsummer onwards, the smaller species of allium with looser-packed, drooping flower heads can make a less showy entrance into the border. The little yellow Allium moly, originally from the mountains of Spain, does well with an accompaniment of Euphorbia dulcis 'Chameleon' and perhaps a silvery helping of stachys of lamium. There's a lovely native of California, A unifolium (syn murrayanum) with large, pink flowers, which will expand to form a decent-sized clump over the years. It is well worth acquiring, and fun to combine with ... well, that's something you may want to think about yourself.