Alliums all come from the onion family but Allium giganteum is an ever popular ornamental plant often used singly, or in clumps in borders, to heighten the overall effect. This bulbous perennial produces a flower which can stand 4-5ft above ground level in maturity. With us it is more commonly 3-4ft tall. The bulb produces large strap-shaped green leaves at the base which shrivel and wither away before the flower spike, with its 4in circular lilac-pink flower head, appears. A very ‘tidy’ plant in the border which is absolutely no trouble and very easy to grow. The individual flowers in the cluster are star shaped with prominent stamens. Perhaps 40 to 50 individual flowers in each cluster.
A. giganteum originates from central Asia in mountainous areas and is therefore perfectly frost hardy in the UK. Individual bulbs can be planted in the autumn or, more normally, in early spring at a depth of 3-4in. A plant with such a tall flowering stem needs to be planted more deeply than many other bulbs to ensure that the flowers stay upright. Flowering will occur in June or July; possibly later if the bulbs are only planted in late spring.
Flowering stems can be cut and dried when flowering finishes or you can wait and gather the seeds within the circular seed head in early autumn. The seed can be sown immediately or in the spring in a cold frame but it will take several years for the tiny bulbils to develop into bulbs large enough to produce flowering spikes. Rather easier is to lift the main bulbs in the autumn and remove the onion-like offsets for moving or potting on initially. These offsets will develop into flowering bulbs much more quickly than when grown from seed.
Handle the bulbs with gloves to avoid any (mild) skin irritation.
