Tips to get the best from your alliums

20th Sep 2022

Alliums are bulbous perennials, with long-lived pompom flowers that bloom for weeks on end, bridging the gap between spring and summer. They are loved by bees, coming in shades of purple, pink, blue, white and sometimes yellow. They look fantastic when planted in large groups or mixed in with other perennials.

When do I plant allium bulbs?

The best time to plant them is in the autumn between September and November, but they can be planted as late January – if the soil is soft enough to dig a suitable hole! Plant allium bulbs in a sunny position in well-draining soil. They will flower in late spring, May-June.

How do I plant allium bulbs?

Plant alliums in a sunny position. They like plenty of water and sun and prefer free draining soil. Alliums come in a large range of sizes, the bigger alliums can be planted 20cm deep, mid-sized alliums like Purple Sensation can be planted 10cm deep and small alliums can be planted 5-8cm deep. As a general rule, make sure the hole is at least twice the depth of the bulb, but this can be up to four times the depth, it’s better too deep then too shallow. Leave a gap of at least 3x the width of the bulb between each one. For small to medium-sized bulbs (such as the ever popular ‘Purple Sensation‘), this is around 10-15cm (4-6in) deep and 10-15cm (4-6in) apart.

Where do I plant allium bulbs?

Alliums do best in a sunny spot in well-drained soil, but they aren’t fussy about soil type. Plant taller varieties towards the back of a border and shorter-growing types in the front. Alliums are well suited to growing in pots but their foliage can look unattractive after flowering.

How many allium bulbs should I plant together?

Alliums produce lots of thick foliage that starts to die off once the bulb begins to flower. This often means they’re better suited to the middle of a border where the faded foliage will go unnoticed while the flowers put on a show. To avoid seeing the faded foliage, plant alliums in amongst perennials and other plants. Allium flowers range in size, from just a few centimetres to over 20cm (8in) in diameter (Allium cristophii), while the height of alliums can vary significantly, too. This means you can create a spectacular display by planting them in clusters, or else you can use them as features in part of a more varied display.

Do I need to soak allium bulbs before planting?

No, allium bulbs do not need to be soaked before they are planted.

Should I water my allium bulbs after planting?

To help the bulbs settle and grow roots quickly, it’s important to water them well after planting, but after that you won’t have to water them again. Alliums are drought tolerant and watering of plants grown in the ground is not usually necessary. Plants dislike summer irrigation because this may cause the bulbs to rot.

How do I care for my alliums?

Taller types of allium may require support. Once the flowers have faded leave them on the plant until they fall apart as the seed heads are attractive and provide fantastic winter interest.

Allium bulbs can be left in the garden year after year, but remember where you’ve planted them so that you don’t damage them when working on your garden. They can fade or rot if they are planted in the wrong place – such as in soggy soil or in a shady area.

Will allium bulbs spread?

Some allium species spread vigorously through seeds or multiplication, but many varieties do not spread at all. The allium bulbs that do multiply should be divided every three to four years, simply dig around the plant with a trowel and lift the bulbs out. You should be able to separate the bulbs gently with your hands. Alliums can be grown from seed, but bear in mind that this is a long process, so it will be years before you have a flowering plant.

Buy allium bulbs online

We sell a wide variety of allium bulbs of different sizes, colours and that flower at slightly different times throughout the spring and the summer. Most allium flowers are purple but there are also blue, white, yellow and pink varieties. And if you can’t decide, we sell a great allium bulb collection!

Shop allium bulbs now >

Plant allium bulbs