Alliums are part of the onion family, but they're grown for their dramatic flowers rather than flavour. You'll spot them by their globe-shaped blooms in shades of purple, white or pink. They’re brilliant for adding height and structure to beds, and bees can’t get enough of them.

Can you grow Alliums from seed?

Yes, but it’s a long game. Alliums grown from seed can take 2 to 5 years to flower, depending on the variety. For best results, sow fresh seed in a well-drained, gritty compost and keep it warm (around 13°C) to encourage germination. It’s a rewarding process if you’ve got the patience. Otherwise, planting bulbs is your shortcut to a spring show.

Are Alliums poisonous to animals?

They are, yes. Like garlic and onions, ornamental alliums are toxic to pets if eaten. That includes cats, dogs and horses. Best to keep them out of reach if you’ve got any curious four-legged friends.

How tall do Alliums grow and what’s the tallest variety?

Heights vary widely. Smaller types like Allium Moly stay around 25 to 30 cm, while dramatic varieties like Ambassador and Allium Stipitatum can reach up to 1.5 m. Globemaster and Gladiator are firm favourites for big, bold borders.

What’s the best Allium for impact in a mixed border?

Go big or go home. Varieties like Globemaster, Gladiator and Pinball Wizard make a serious statement. Their huge flower heads and long stems create instant architectural drama.

Are Alliums perennials?

Yes. Alliums are hardy perennials. Once planted, they’ll return year after year, often with more blooms as they settle in. Just give them good drainage and plenty of sun.

Do Alliums self-seed?

Some varieties do. If left to go to seed, you may notice seedlings popping up the following year. These may take a few seasons to flower and won’t always be identical to the parent plant.

Do Allium bulbs multiply?

They do. Most alliums produce small offset bulbs underground. Over time, these build into clumps, creating a fuller display if left undisturbed.

When should I cut back Alliums?

Let the foliage die back naturally after flowering. It feeds the bulb for next year’s growth. Once it’s yellowed and withered, you can trim it back. If you like the look of the seed heads, leave them standing for late-season structure. You can find more information about planting and growing alliums in the Allium Growing Guide.

Do slugs eat Alliums?

Rarely. Alliums are generally slug- and snail-resistant, making them a great low-maintenance option for wildlife-friendly or no-dig gardens.

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Allium Bulbs

Allium Bulbs

Allium bulbs, otherwise known as ornamental onions, are a must have for colourful late spring display, bridging the gap between the spring flowering bulbs such as Tulips and Daffodils and the early summer flowering perennials such as Aquilegia and Delphiniums. Their flowerheads normally present in varying shades of purple, but we also offer a range of white, pink and even yellow varieties.

We offer a large range of alliums, ranging from classics such as Allium Purple Sensation, Allium Sphaerocephalon and Allium Globemaster to newer, more unusual varieties such as Allium Hair and Allium Fireworks.

Equally at home in borders (the majority of alliums are best placed in the mid section due to their height range), or used to create a statement in either a pot or a raised bed, alliums are not only impressive in their ability to produce statement flowerheads year after year, but also due to them being magnets for pollinators such as bees and butterflies.

Regarding companion plants, full information (and inspiration) can be found in our article ‘What to plant with allium bulbs’, but perennials such as Salvia and Verbascum, along with grasses such as Panicum and Pennisetum are beautiful, yet reliable options.

Alliums are fairly easy to grow - they prefer a sheltered, well draining site, but work in the majority of soils. For full growing information, please refer to our Allium Growing Guide or find answers to specific questions such as ‘When is it too late to plant Allium Bulbs’ on our blog, or below.

FAQs:

What is an Allium?

Alliums are part of the onion family, but they're grown for their dramatic flowers rather than flavour. You'll spot them by their globe-shaped blooms in shades of purple, white or pink. They’re brilliant for adding height and structure to beds, and bees can’t get enough of them.
Can you grow Alliums from seed?

Yes, but it’s a long game. Alliums grown from seed can take 2 to 5 years to flower, depending on the variety. For best results, sow fresh seed in a well-drained, gritty compost and keep it warm (around 13°C) to encourage germination. It’s a rewarding process if you’ve got the patience. Otherwise, planting bulbs is your shortcut to a spring show.
Are Alliums poisonous to animals?

They are, yes. Like garlic and onions, ornamental alliums are toxic to pets if eaten. That includes cats, dogs and horses. Best to keep them out of reach if you’ve got any curious four-legged friends.
How tall do Alliums grow and what’s the tallest variety?

Heights vary widely. Smaller types like Allium Moly stay around 25 to 30 cm, while dramatic varieties like Ambassador and Allium Stipitatum can reach up to 1.5 m. Globemaster and Gladiator are firm favourites for big, bold borders.
What’s the best Allium for impact in a mixed border?

Go big or go home. Varieties like Globemaster, Gladiator and Pinball Wizard make a serious statement. Their huge flower heads and long stems create instant architectural drama.
Are Alliums perennials?

Yes. Alliums are hardy perennials. Once planted, they’ll return year after year, often with more blooms as they settle in. Just give them good drainage and plenty of sun.
Do Alliums self-seed?

Some varieties do. If left to go to seed, you may notice seedlings popping up the following year. These may take a few seasons to flower and won’t always be identical to the parent plant.
Do Allium bulbs multiply?

They do. Most alliums produce small offset bulbs underground. Over time, these build into clumps, creating a fuller display if left undisturbed.
When should I cut back Alliums?

Let the foliage die back naturally after flowering. It feeds the bulb for next year’s growth. Once it’s yellowed and withered, you can trim it back. If you like the look of the seed heads, leave them standing for late-season structure. You can find more information about planting and growing alliums in the Allium Growing Guide.
Do slugs eat Alliums?

Rarely. Alliums are generally slug- and snail-resistant, making them a great low-maintenance option for wildlife-friendly or no-dig gardens.