Allium schubertii

Allium schubertii: how do you recognise it?

Bulb

Round bulb about 5 cm across with a brown skin; plant it in autumn.

Leaves

A few broad, strap-shaped, grey-green leaves that appear in spring and die back around flowering.

Flowers

A loose head up to 40 cm across of pinkish-purple, star-shaped flowers on stalks of very different lengths, in June.

Stem

Sturdy and bare, 30–50 cm tall.

Seed head

After flowering the whole head dries into a straw-coloured star full of seed capsules.

Flowering: June · Plants: September–October

Why grow it?

• A spectacular firework of a flower head up to 40 cm across: a real eye-catcher in June.
• Bees and bumblebees visit the many small flowers.
• A striking cut flower; dried, the head stays decorative for months.
• Drought tolerant: ideal for a gravel garden or a sunny, dry border.
• Also suitable for a large pot on a sunny patio.

Allium schubertii: where does it grow best?

• Full sun, as warm as possible: for example in front of a south-facing wall or in a gravel garden.
• Sandy or loamy, very well-drained soil, neutral to chalky.
• Dry, especially in summer and winter when the bulb is dormant. Wet soil in winter makes the bulb rot.
• On heavy or wet soil: grow it in a pot or a raised bed with coarse sand or grit.
• Plant 30–40 cm apart so the large heads do not touch.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry

Size

0.5 m tall, 0.4 m wide

Hardiness

Half hardy (to -12 °C): protect it in harsh winters

Goes well with

• Catmint: Hides the dying leaves and flowers in blue at the same time.
• Feather grass: Airy stems that sway in the wind with the stars.
• Lavender: The same warm, dry spot and a fine purple contrast.
• Spurge: Grey-green leaves and a strong shape for the gravel garden.
• Perennial sage: Upright purple spikes at the same time.

Allium schubertii: when and how to plant it?

Plant in September–October.

1. Plant the bulbs in September–October.
2. Dig a hole for each bulb and put a layer of coarse sand or grit in the bottom for drainage.
3. Plant the bulb 10–15 cm deep, pointed end up.
4. Space them 30–40 cm apart, ideally among low perennials that will later hide the dying leaves.
5. Water once if the autumn is dry; after that rain is enough.
6. In a pot: use potting compost mixed with a third coarse sand or grit, in a pot with a drainage hole.

Care

Watering

Usually not needed after planting. In spring only during long droughts; keep dry after flowering.

Feeding

Not needed in the garden. In a pot, a little bulb fertiliser in spring.

Leaves

The leaves die back during flowering. Let them wither naturally and remove them only when completely dry.

Faded flowers

Leave the head standing as a sculpture or cut it for a dried arrangement. If you do not want seedlings, cut it off before the seed ripens.

Cut flower

Cut the stems when most of the flowers are open; they last a long time in a vase.

Tip: Give it a warm, dry spot in full sun; on wet soil, grow it in a pot that you keep dry in winter. After flowering, leave the dried head standing: it remains a sculpture for months.

Allium schubertii: when to prune it?

When: A bulb does not need pruning. After flowering you can at most cut off the stem.

How:

• Leave the faded head to dry in place, or cut it for a dried arrangement.
• Let the leaves die back completely: they feed the bulb for next year’s flowers.
• Remove dried leaves and stems only when they are brown and come away easily.

Caution: Do not cut the leaves while they are green: the bulb would build up too few reserves and flower less next year.

Pruning calendar and basic rules

Propagation

Offsets

Small bulbs form around the main bulb. Lift it once the leaves have died down, separate them and replant in autumn. They flower after a few years.

Seed

Sow ripe seed in autumn in a pot of gritty seed compost and leave it outdoors. Seedlings take several years to flower.

Allium schubertii: how does it get through the winter?

Hardy to −12 °C: protect in harsh winters.

• Moderately hardy, to about −12 °C. In a normal Belgian winter it survives in dry, well-drained soil, but cold and wet together are dangerous.
• In winter cover the planting spot with a layer of grit, dry leaves or conifer branches.
• On wet soil: grow it in a pot and keep the pot dry and frost-free in winter, for example in a cold garage or under cover.
• Pots left outdoors: protect them from too much rain and wrap them in hard frost.

Diseases and pests

• Bulb rot: The bulb rots in wet, heavy soil. Plant in a dry, well-drained spot or in a pot with coarse sand.
• Slugs: They eat the young leaves in spring. Pick them off in the evening.
• Yellow leaves at flowering: Normal: in this species the leaves die back during flowering. Hide them behind low perennials.
• Few or no flowers: Too cold, too wet or too shady. Move the bulbs to a warmer, drier spot.

Through the year

• March: The first leaves appear. Watch for slugs.
• April: Leaf growth. Water only during long droughts.
• May: The flower bud appears.
• June: Flowering: a firework of pinkish-purple stars. Cut for the vase.
• July: The flower head dries: leave it or cut it for drying. Let the leaves die back.
• August: Remove dead leaves. Lift offsets if wanted.
• September: Plant bulbs 10–15 cm deep.
• October: Plant bulbs. Sow seed in a pot.
• November: Cover the planting spot with grit or dry leaves.
• December: Move pots to a dry, sheltered place.

Edible and useful

Not edible. Ornamental onions are true alliums, related to onion, garlic, leek and chives, and like them they are poisonous to dogs and cats: all parts, especially the bulbs, contain sulphur compounds that damage the red blood cells and can cause anaemia. Cats are more sensitive than dogs, and the signs (lethargy, pale gums, red or brown urine) sometimes appear only after a few days. Horses, sheep and other livestock can fall ill from them too. Even though the leaves and bulbs smell of onion, they are not grown as vegetables: do not eat them, and never store the bulbs with the kitchen onions, as they are not meant for eating and may have been treated with pesticides. Do not plant them where your dog digs, keep loose bulbs out of reach of pets and children, and do not put a vase of alliums where your cat chews the stems. If your dog or cat has eaten a bulb or leaves, call your vet, even if it shows no signs yet. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• It is also called tumbleweed onion: in its dry homeland the dried flower head breaks off and rolls along in the wind, scattering its seed.
• The flower head dries so well that it is often used in dried arrangements and floral displays.
• It is related to onions, leeks and garlic, and like them its leaves smell of onion when crushed.