Alliums
Ronald Blom wrote in 2005 that alliums were the perfect answer to that in-between time, when the daffodils and tulips have died down and the herbaceous plants are not yet showing. Twenty years on it is still the best description of what they do. They run from small delicate species up to heads the size of a football.
Go BackAbout Alliums
The genus takes in garlic, onions, shallots and even leeks, which is why the ornamental sorts are often called ornamental onions. What we grow them for is the shape. Nearly all of them carry a round head of flowers on a tall bare stem, and that outline does something in a border that very little else manages. It adds structure and form, and draws the eye, particularly among the larger varieties.
They range from the small and delicate, cowanii and moly Jeannine among them, up to Gladiator and Globemaster, whose heads can measure as much as 25cm across on a stem stout enough to shrug off bad weather. Taller sorts circled about with smaller ones is a combination well worth trying.
The Two Honest Drawbacks
The foliage is not their strong point. It is narrow and strappy, and on many of the taller species it is dying back just as the flowers open, so they are best planted among leafier neighbours who will cover for them. The leaves also smell distinctly of onion when crushed. The remedy there is simply not to tread on them.
Buy Them as Bulbs, Not in the Green
Alliums are sold in great numbers as potted plants in spring, bought on impulse during a garden centre trip. They perform far better planted as dry bulbs in the autumn, the choice available to you is very much wider, and they cost a good deal less. It is one of the clearest arguments in the whole catalogue for thinking a season ahead.
Growing Them
Full sun suits them best, though they will tolerate a little shade, and what they want above all is drainage. Left undisturbed they establish themselves and flower year after year, and it is not uncommon for seedlings to appear of their own accord. Keep the ground around them clear and well weeded, which is what produces strong straight stems.
When Do Alliums Flower?
Mostly through May and June, filling the gap between the last of the tulips and the first of the summer perennials. The dried heads then stand for weeks afterwards, which is one reason flower arrangers are so fond of them.
