Allium sphaerocephalon, also known as the drumstick allium or round-headed leek, is a summer-flowering allium with ramrod-straight stems that reach between 60 and 90cm (2-3 ft). Each slender stem is topped by a small, oval chartreuse-green head tinged with maroon-claret at the tip.
Where to plant
Like most bulbous plants, alliums, or ornamental onions, do best in sunny, well-drained positions. They are perfectly hardy and will come back year after. And they are not aggressive self seeders - like some ornamental alliums.
Drift it through borders en masse to provide light vertical accents, or plant it in clusters of nine, eleven or fifteen. Buy at least 50, scatter them randomly through a sunny border Or you can pot them up in fives or sevens and plant them out in any gaps.
When to plant
The ideal time for planting all alliums is September. However, they can also be planted in spring, although they may not flower as well in their first year.
How to plant
Plant Allium sphaerocephalon to a depth of three inches aiming to form a ribbon of colour. Allium sphaerocephalon needs to be planted and left to get on with it. It will die down every winter and reappear in spring and occasionally you may have to plant a few more bulbs.
When it flowers
Allium sphaerocephalon flowers at the beginning of July, much later than most purple and lavender alliums. It has slender, willowy stems topped with egg-shaped heads that start off lime-green and then morph into rose-purple. The flowers last for weeks, before fading to bleached canvas in autumn.
Grow Allium sphaerocephalon with a haze of summer grasses including the fine-tined ponytail grass Stipa tenuissima and the feathery S. barbata. Or create a contrast with the non-stop orange geum ‘Totally Tangerine’. Plant in generous groups (sevens, nines or more) for impact – singles won’t do.
Allow to form a greyish seedhead, then pull away the stem in early autumn. Replant regularly as some will disappear.
Buy Allium sphaerocephalon from Saga Garden Centre