Tumbleweed onion

Sun

Full sun; avoid sites shaded by taller plants during spring growth.

Water

Water moderately during active spring growth if rainfall is scarce. Keep relatively dry during summer dormancy; persistent wetness can rot the bulbs.

Soil

Very well-drained sandy, gritty or gravelly soil. Tolerates a range of soil pH but performs poorly in heavy, waterlogged ground.

Height

1-2 ft (0.3-0.6 m)

Spread

1-1.5 ft (0.3-0.45 m), including the flower head

Flowers

Late spring to early summer; loose, starburst heads of pale pink to pinkish-purple flowers, often 1 ft (0.3 m) or more across.

Foliage

Broad, strap-shaped, blue-green leaves emerge before flowering and often begin yellowing as the flowers open. Summer dormant.

Growth

Moderate; established bulbs flower each year in suitable conditions, but clumps increase slowly.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.5 ft (0.15 m)

2. After 1 year

   1.2 ft (0.38 m)

3. After 2 years

   1.5 ft (0.45 m)

   full size

About 1 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Growth rate

Slow

• Plant bulbs in autumn, about 4-6 in (10-15 cm) deep and 12-18 in (30-45 cm) apart.
• Use a raised bed or container with drainage holes if your soil stays wet in winter.
• Water during prolonged dry spells while leaves are green; stop routine watering once they die back.
• On poor soil, apply a light dressing of balanced fertilizer as growth starts in spring.
• Keep thick, moisture-holding mulch away from the bulb crowns.
• Lift and separate crowded offsets after the foliage has died back, then replant promptly.

Pruning. Leave leaves untouched until they have completely yellowed, then remove them. Keep dried flower heads for display or cut the stems at the base before seeds scatter.

Autumn

Plant bulbs in full sun and sharply drained soil.

Winter

Check that containers and planting beds drain freely; avoid standing water.

Early spring

Watch for emerging leaves and feed lightly if the soil is poor.

Spring

Water during prolonged dry weather while the foliage is actively growing.

Late spring to early summer

Enjoy the flowers or cut stems for fresh and dried arrangements.

Summer

Remove fully yellowed leaves, reduce watering and divide crowded bulbs if needed.

• Plant in gravel gardens where the open flower heads stand clearly against stone and low foliage.
• Repeat small groups through sunny borders for a strong late-spring accent.
• Combine with low, drought-tolerant perennials that soften the dying foliage without shading spring growth.
• Grow in a freely draining courtyard container, leaving room for the wide flower heads.
• Leave dried heads among low grasses for summer structure.

Garden styles it suits: Architectural minimal, Dry gravel garden, Mediterranean, Contemporary minimal, Cottage garden and Pollinator garden.

Plant it with: Catmint, Lavender, Creeping thyme, Lamb's ears, Hardy geranium and Blue fescue.

Wildlife: Flowers provide nectar and pollen for bees and other visiting insects. Deer and rabbits usually avoid the onion-scented foliage, though no plant is completely browse-proof.

• Bulb rot in wet ground: improve drainage or move bulbs into a raised bed; discard soft, rotting bulbs.
• Allium leaf miner in affected regions: remove damaged foliage and infested bulbs, and follow local guidance on pest timing and disposal.
• Slugs and snails damaging young leaves: check emerging growth and use hand-picking or suitable barriers and controls.
• Poor flowering: give bulbs full sun, leave foliage until yellow, and divide overcrowded clumps after dormancy begins.

All parts, including bulbs, leaves and flowers, are toxic to cats, dogs and horses if eaten; Allium poisoning can damage red blood cells and may be serious. It is not a culinary onion: ingestion by people can cause stomach upset, so keep bulbs away from food supplies and children.

• Star of Persia (Allium cristophii)

  Has a more evenly rounded head of metallic violet, star-shaped flowers on stalks of more uniform length; tumbleweed onion has a much more irregular, explosive outline.

• Tripoli onion (Allium tripedale)

  Has hanging, bell-shaped pink-and-white flowers rather than the outward-facing starry flowers and widely unequal stalks of tumbleweed onion.

The common name refers to the dried, rounded flower head, which can break free and roll in the wind, scattering seeds.

Propagation. Separate offsets after the leaves die back in summer. You can also sow ripe seed in a well-drained mix outdoors; seedlings vary and usually take several years to reach flowering size.

Accepted botanical name

Allium schubertii

Native range

Lebanon-Syria, Libya, Palestine and Turkey.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.