When and How to Plant Allium Bulbs

Easy to grow and versatile, Alliums (otherwise known as Ornamental Onions) have become a popular plant for modern gardens. Available in an assortment of shades and sizes, these versatile plants are perfect for any garden, big or small.

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!

Our favourite Allium varieties:

Allium ‘White Cloud’
Allium ‘Summer Drummer’
Allium ‘Gladiator’

Allium Guide: When and How to Plant Them

Alliums are plants of exquisite beauty that deserve a place in perennial gardens. Easy to grow and undemanding, these ornamental bulbs come in a diverse range of colour, height and bloom times, to give you beautiful blooms from spring all the way through till summer.

Throughout this Allium blog, we will guide you through our most popular varieties, planting partners, a full planting guide and even video planting tutorials to get you ready for your autumn bulb planting.

Planting Guide

Planting time: September – December 📆

Location: Full Sun/Partial Shade ☀

Flowering Time: Late-Spring-July 🌸

Soil Type: Fertile, well-drained soil 🏡

For ground planting:

  1. Remove any weeds before planting.
  2. Plant at 3-4 times the depth of the bulb and approx 10cm-15cm apart. Position the bulbs with the pointed end facing upwards.
  3. Fill in the holes and tread down lightly.
  4. Feed regularly in poor soils.
  5. After flowering, remove the leaves when they have withered.

For container planting:

  1. Make sure to use a deep and fairly large pot for large Allium bulbs.
  2. Use a good-quality potting compost.
  3. Plant the bulbs three times deeper than the height of the bulb and as far apart as you can.
  4. Water sufficiently after planting.
  5. For frost protection, use bubble wrap or garden fleece.

Top Varieties

Allium Graceful Beauty

A striking new variety. This elegant Allium will dazzle in the summer garden with their white and pink flushed flowers. Easy to grow and compact, this bloomer will dazzle at the front of the border. Also they are perfect for attracting wildlife!

Click here to view online.

Allium Drumsticks

A lovely addition to the border. Add interest and movement to the late-spring garden with these unique and vibrant egg-shaped flower heads.  As well as being long lasting and pollinator-friendly, these Alliums make beautiful cut flowers!

Click here to view online.

Allium Gladiator

An RHS Garden Merit Award-Winner. Allium Gladiator showcases dozens of small star-shaped purple blooms which are long lasting and naturalise easily for years of pleasure. Spectacular in large, sweeping drifts.

Click here to view online.

 Allium Globemaster

Boasting massive spherical violet heads, this award-winning Allium is a great tall addition to beds and borders. This showstopper naturalises easily and they are perfect for bringing butterflies fluttering to the garden.

Click here to view online.

Alliums look beautiful alongside…

Forming a succulent mat of foliage around the base, then springing into flower some time after the Alliums have faded. Click here to view our Sedum Range.

Partner the taller Allium varieties alongside delphiniums for a border filled with architectural beauty and height. Click here to view our Delphinium Range.

Create a border rich in colour and shapes. Poppies and Alliums both excel in the garden as elegant vertical accents with architectural interest. Click here to view our Poppy Range.