They attract butterflies, do not smell like onions (although the foliage and bulbs often do), and, when happy in their full-sun, well-drained site, can form colonies or self-seed, especially when some of the more humongous flower heads are left on the plant, creating a startling, dried flower arrangement in the middle ...

Do allium seeds turn into bulbs?

Allium sphaerocephalon is a variety which produces aerial bulbils – these grow from out of the flowerhead. These can be planted in the same way as described above. A happy allium will self-seed freely.

Do alliums spread?

After a few years allium bulbs will multiply. In some cases you'll notice the white bulbs being pushed out of the soil. In late autumn or very early spring carefully lift the bulbs and gently peel off the offsets to replant straight into the soil.