The popularity of these ornamental onions shows no sign of waning - and with good reason, for they are a dramatic addition to any hot sunny border. As a general rule the foliage will emerge first and then die down as the flower stems emerge. It is often best to plant them with other plants that will mask the unsightly foliage as it dies back. After flowering we find it important to dead head them by removing the flower head but leaving the flower stalk. This will allow the plant to put enough energy back into the bulb to ensure a good show the following year. If you want to preserve the seed heads on the plant to provide winter interest wait until the bulb is old enough to produce several flower heads and then remove half after flowering, providing you and the bulb with a good compromise.
How to plant allium bulbs:
Alliums thrive in a free-draining soil in full sun. Plant any time between September and November.
In borders - add some grit to the bottom of the planting hole if your soil is not free-draining. This reduces the chance of the bulb rotting off over the winter. Plant three times the diameter of the bulb. Larger species should be spaced aprrox. 20cm apart, smaller species about 10cm apart. The taller drumstick vareities look good in small clumps or dotted through a border to act as vertical highlights.
In pots - use either a good quality multi-purpose compost, or for best results add in 20% John Innes loam-based compost and 20% washed horticultural grit. Make sure there are good drainage holes in the pot, and use crocks or broken pot pieces at the bottom to stop the drainage holes getting clogged.