A. caeruleum

Description

Height 60cm/2ft. Blue flowers are produced in June and July

Cultivation

The larger alliums are suited to herbaceous borders or mixed beds, while the smallest species are grown in rockeries. They will grow on all soils providing that they are well drained, but require an open aspect in full sunshine. The bulbs vary considerably in size depending upon the species. Plant at two and a half times the bulb's depth. Plant small bulbs 15cm/6in apart, middle sized bulbs 30cm/1ft apart, and the very largest as solitary subjects to the side or back of the beds. When the flowers have died the heads should be removed and the leaves allowed to die down naturally. To ensure good bulbs for the following year, give a feed with a quick-acting fertiliser as soon as the flowering shoot begins to emerge and again prior to the bloom opening. Do not lift the bulbs in the summer. When the clumps become over-large, wait until the following spring, then as soon as the shoots begin to emerge lift the whole clump, taking care not to damage the roots; divide and replant.

Propagation

Seeds can be gathered and kept until the following February when they should be sown in gentle warmth. Germination tends to be variable – some species take several months. When grasslike seedlings reach 5cm/2in tall, transplant each to an individual flower pot and allow it to grow without interruption until the following summer. The plants can then be transferred to their permanent positions, or to a nursery bed until they have produced the first flowers.

Pruning

N/A