When and How to Plant Allium Bulbs

Posted by Shannen Godwin on 17th Jun 2021

When and How to Plant Allium Bulbs

Easy to grow and versatile, Alliums (otherwise known as Ornamental Onions) have become a popular summer plant for modern gardens. Available in an assortment of shades and sizes, these beautiful blooms are perfect for any garden, big or small. Discover when to plant allium bulbs and how in our gardening guide.

When to plant Allium bulbs?

To grow these eye-catching blooms for the late spring/early summer garden, Allium bulbs should be planted in early autumn (September-October).

How to Plant Allium bulbs

  1. Pick your location

    Alliums thrive in sheltered areas that receive full sun. They do not like to be exposed fully to the elements. Depending on the height of the allium, tall alliums look great at the back of a border and small varieties are well-suited for containers.

  2. Soil type

    Alliums will grow perfectly well in a well-drained soil. They hate waterlogged soil.

  3. Planting in the ground

    Plant the bulbs at a depth of roughly 3-4 times the size of the bulb. Space larger bulbs approx. 15cm apart but smaller bulbs can be spaced about 10cm apart.

  4. Planting in pots/containers

    Deep pots are most suitable for Alliums. Simply use a multi-purpose compost in a pot with adequate drainage, and water well.

    Tip – Broken pots or stones placed in the bottom of the pot will help improve drainage.

Common Allium questions:

When should I feed Alliums?

Feed your Alliums in the spring with a potash-rich fertiliser.

How long do Alliums flower for?

Alliums usually flower for around 3-4 weeks.

What do I do with Alliums after they flower?

After the foliage dies down, you can cut the plants down to the ground and leave them or divide them.

Tip: Leave Allium seed heads after they’ve finished flowering for the garden birds to enjoy!


Fan Favourite Alliums to Try This Spring

Imaged: Allium sphaerocephalon


Allium Gladiator
Allium Globe Master
Allium sphaerocephalon
-
 Allium Purple Sensation
Allium Karatieviense
Allium Mount Everest
Allium stipitatum

Want to learn more about how and when to plant allium bulbs, or general tips on how to make them thrive? Our allium growing guide outlines everything you need to know about these sensational spring to summer plants.