Allium Bulbs — Plant in Autumn for Early Summer Globes
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Ornamental alliums are autumn-planted bulbs that send up tall globes of purple, white and blue flowers in early summer, and they cope well in Irish borders as long as the soil drains freely. Free tracked delivery across Ireland and 24 more EU countries.
When and how to plant allium bulbs in Ireland
Plant alliums from September to November in full sun and well-drained soil, about three times the bulb's height deep, pointed end up. They flower in May and June, and the seed heads stay decorative well into summer.
| Bulb | When to plant | Depth | Spacing | Light | Flowers |
|---|---|---|---|---|---|
| Allium 'Purple Sensation' | September–November | 10–20 cm | 15–30 cm | Full sun | May–June |
| Allium 'Gladiator' and 'Pinball Wizard' | September–November | 15–20 cm | 25–30 cm | Full sun | May–June |
| Allium christophii (Star of Persia) | September–November | About 3× bulb height | 15–30 cm | Full sun | May–June |
| Allium siculum (Sicilian honey garlic) | September–November | About 3× bulb height | 15–30 cm | Full sun | May–June |
| Allium caeruleum and Allium sphaerocephalon | September–November | About 3× bulb height | 15 cm | Full sun | Early summer |
Getting the best from alliums
Drainage matters more than cold: wet, waterlogged ground rots bulbs, so on heavy soil add grit or plant on a slight mound. Large globes such as 'Gladiator' and 'Pinball Wizard' need 25–30 cm between bulbs; smaller types such as 'Ping Pong', 'Purple Rain' and the 'Buzzing Beauties' mix can go closer together in groups.
Alliums are excellent for bees, so plant them where you will see the activity. Their leaves often start to fade as the flowers open, so tuck them behind lower perennials. Leave the foliage for about six weeks after flowering so the bulbs build up for next year, and if squirrels or mice dig them up, cover the area with chicken wire until shoots appear.
Frequently asked questions
When should I plant allium bulbs in Ireland?
Any time from September to November. Earlier planting gives the roots longer to establish before winter, but bulbs planted in November will still flower the following summer.
How deep do you plant allium bulbs?
About three times the height of the bulb, which works out at 10–20 cm for the large-flowered types, with the pointed end facing up.
Can you grow alliums in pots?
Yes, provided the compost drains well. Use a deep container and try lasagne layering, with alliums at the bottom and smaller early bulbs such as crocus or muscari above them.
Pair alliums with tulip bulbs for a longer run of colour, see our pollinator garden plants, or read the autumn planting guide for Ireland.
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