ornamental garlic

The bulbs stay in the ground in winter; digging them up is not necessary. Good drainage matters more than frost protection: waterlogging makes the bulbs rot faster than cold does, so on heavy loam soil add a layer of sand under the bulb and avoid wet sites. Giant alliums in tubs are more exposed and need protection: wrap the pot in horticultural fleece or a hessian sack and stand it on an insulating base.

The giant allium can be propagated in two ways: by offset bulbs and by seed.

Offset bulbs (preferred method): Over the years, the mother bulb forms daughter bulbs and bulblets. In autumn (September to November), carefully dig up the bulbs and gently detach the firm, white offset bulbs. Plant them straight away in their new position in a sunny spot, smaller offset bulbs about 10 to 15 cm deep, with enough space (around 15 to 25 cm). This method gives plants true to variety and flowering-size specimens much faster than sowing: they often flower as early as the following year.

Sowing: Leave the spent flower globes on the plant until seed capsules form. Harvest the black, shiny seeds shortly before the capsules open. The giant allium is a cold-stratification seed. For autumn sowing directly outdoors, put the seed about 1 cm deep in the soil; it receives the necessary cold stimulus over the winter by itself. For raising indoors, first stratify the seed for a few weeks in a moist, warm place, then for 6 to 8 weeks in the cool at 0 to 4 °C (e.g. in the refrigerator), and sow it in spring afterwards. Expect plants grown from seed to flower for the first time only after 2 to 3 years. Note also: varieties and hybrids do not come true from seed; for true-to-variety propagation, offset bulbs are the safe way.