What soil does Ornamental onion grow in?

It tolerates these soils: average garden soil, sandy.

Is Ornamental onion hardy?

Hardy down to -29 °C (USDA zone 4, RHS H7). It gets through winter in every part of the country.

When does Ornamental onion flower?

Flowering: May–July, purple, white, pink.

How much water does Ornamental onion need?

Water need: low. Drought tolerance: high.

How much does Ornamental onion cost?

It sells for roughly €5.90 to €35 in local shops, depending on size.

Ornamental onion

Allium × hybridum

Ornamental onion (Allium × hybridum) is a perennial. Light: full sun. Hardy down to -29 °C. Drought tolerance: high. Toxic to dogs and cats. Sold in local shops from about €5.90.

Illustration of Ornamental onion — An illustration of the typical shape of the mature plant, not a photo.

What it's good for, and what it isn't

Tall ornamental onions flower in late spring and early summer: their purple, white or pink globes on bare, straight stems fill the gap between tulips and summer perennials, bees and butterflies love them, and deer and rabbits avoid them because of the onion smell. Plant the bulbs in autumn in a sunny, well-drained spot at three times their diameter (large bulbs 15-20 cm deep, small ones 8-10 cm), the big-headed kinds 20-30 cm apart, in groups of at least five to seven. The leaves start to yellow as the flowers open, so set them among low perennials or grasses that hide the base, but let the foliage die back on its own; the dry seed heads stay decorative for a long time. Cultivars differ a lot: heads range from tennis-ball to volleyball size and stems from 50 cm to a metre and a half, some persist for years and multiply by offsets, while the largest-headed ones may weaken after a few seasons and the small-headed summer kinds self-seed freely.

Watch out for

In wet, heavy soil the bulbs rot and various fungal diseases (bulb rot, white rot, rust, mildew, leaf spots) can appear, so drainage matters most. The stems of the tallest kinds can be blown over by strong wind, so give them a sheltered spot. Thrips are an occasional pest. Deadhead the kinds that self-seed (mainly the small-headed summer alliums) if you do not want seedlings everywhere.

Key facts

Light: Full sun
Water need: Low
Care: Low
Size after 10 years: 90 cm × 30 cm
Hardiness: down to -29 °C
Foliage: Deciduous
Flowering: J F M A M J J A S O N D May–July, purple, white, pink

Group	Perennial
Light	Full sun
Size after 10 years	90 cm × 30 cm
Ultimate size	0.4–1.5 m × 20–60 cm
Hardiness	down to -29 °C (USDA 4, RHS H7)
Soil	Average garden soil, Sandy
Foliage	Deciduous
Flowering	May–July, purple, white, pink
Water need	Low
Drought tolerance	High
Maintenance	Low
Root aggressiveness	Low
Suckering	no data
Spreading	Medium
Distance from buildings	no data
Distance from paving	no data
Litter	not typical
Planting distance	25 cm
For dogs	Toxic
For cats	Toxic
For children	Mildly toxic (uncertain)
Typical price	from about €5.90

Toxicity data is for information only. If your pet or child has eaten a plant, contact a vet or a doctor.

Sizes and prices available

The same plant is sold as a small pot and as a specimen several metres tall, and the price follows. Prices are rounded and for guidance only.

Size	Typical price
30-50 cm	approx. €16
40-60 cm	approx. €8
size not stated	approx. €5.90 – €35

Frequently asked questions

Data updated: October 8, 2026 · How our data is made

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