When To Plant Alliums. Bulbs you have stored over winter should be planted at the end of their dormant season. Alliums are amongst the most undemanding flower bulbs to plant tolerating most types of soil and hardy down to zone 4.
Gardeners in cold climates will want to plant allium bulbs in September October or November. Wait until nighttime temperatures cool off to about 4050F before planting your bulbs. Alliums that grow from bulbs are planted in the fall after the first frost and before the ground freezes.
When to Plant Allium.
Most types grow from bulbs that are planted in the fall at the same time as tulips and daffodils. Nectaroscordum can tolerate a little more shade as can some of the smaller alliums such as Allium moly. These may be planted at any time during the growing season. Alliums are spectacular plants so its worth saving a few seeds to sow in spring to grow more for the garden.
