Alliums can be propagated by dividing the bulbs or by collecting and sowing the seeds

Dividing the bulbs 

  1. Dig up the plant in the fall or early spring
  2. Separate the bulbs along the visible lines of division
  3. Replant the healthy bulbs in the original space and the remaining bulbs in other areas of the garden

Collecting and sowing the seeds 

  1. Wait for the seedhead to dry
  2. Collect the seeds
  3. Sow the seeds immediately or store them for spring
  4. Sow the seeds directly in the garden in the spring or summer
  5. Start the seeds indoors to speed up germination

Tips for propagating alliums

Bulbs start to multiply after a couple of years, so it’s a good idea to refresh a clump every 3–4 years 

Hybrids won’t be true to the parent plant  It can take several years for alliums grown from seed to reach flowering size  Seeds should be sown while they are fresh and ripe  You can use a knife or saw to split the bulbs