Allium Post Bloom Care: Caring For Allium Bulbs Once Flowering Is Over

By Liz Baessler

Allium, also known as flowering onion, is a spectacular and unusual looking flowering bulb that will add interest to any garden. As the name suggests, allium plants are members of the Allium family, which includes such plants as garlic, onions, leeks, and chives. All of these plants produce similar round, pom-pom shaped flower heads, though alliums are the only ones usually exclusively grown for their flowers. But what do you do with your allium once it’s finished flowering? Keep reading to learn more about how to care for alliums after blooming.

Caring for Allium Bulbs

Allium plants produce big, round, softball sized flowers in shades of purple. They last best in sunny but sheltered spots where the wind is less likely to blow the flowers apart. In these conditions, they bloom in early summer and tend to last for about three weeks.

Once the flowers have faded, you can deadhead the blooms. Leave the foliage in place, though, as the leaves need time to fade naturally to gather energy into the bulbs for next season’s growth. The leaves may look a little straggly, so it’s a good idea to plant alliums in a bed with later blooming flowers that can hide and distract from them.

How to Care for Alliums after Blooming

Allium post bloom care is very easy. Simply keep the plants moderately watered until they fade to yellow and begin to shrivel. At this point, you can cut the plants down to the ground, leaving them where they are or dividing them.

Allium bulbs should be divided every three or four years. To do this, simply dig around the plant with a trowel and lift the bulbs out. There should be a collection of bulbs, which you can separate gently with your hands. Replant a few in the same spot, and plant the others right away in new locations.

Caring for allium bulbs that you don’t want to divide is even easier. Simply cut back the foliage when it fades, and in the fall, cover the soil with 2 to 3 inches of mulch. Remove the mulch in the spring to make way for new growth.

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