Allium bulgaricum (Onion) — Upright bare stems from a bulb

Overview

Allium bulgaricum is a upright bare stems from a bulb bulb in the genus Allium, part of the Amaryllidaceae family, with deciduous; strap-shaped or grassy basal leaves, dying back as the flowers open foliage. Allium bulgaricum grows best in full sun, and tolerates most soils and neutral to alkaline pH. Its UK hardiness is rated H4-H6. It is native to Bulgaria.

About

Allium bulgaricum is a bulbous member of the Amaryllidaceae, sending up upright, mostly bare stems from a bulb and producing its flowers in May to July. It bears strap-shaped, grassy basal leaves that are deciduous and die back as the blooms open. Best sited in full sun on light, free-draining soils of neutral to alkaline reaction. Native to Bulgaria, it tolerates both exposed and sheltered positions.

Wikipedia contributors, CC BY-SA 4.0 — Allium siculum

About the genus

Allium is a large genus of monocotyledonous flowering plants with 1112 accepted species, making Allium the largest genus in the family Amaryllidaceae and among the largest plant genera in the world. Many of the species are edible, and some have a long history of cultivation and human consumption such as the onion, garlic, scallions, shallots, leeks, and chives.

Wikipedia contributors, "Allium", CC BY-SA 4.0 — Allium

In the garden

Allium bulgaricum sits in the genus Allium within the Amaryllidaceae and originates from Bulgaria. Plants emerge from bulbs and produce upright stems topped by flowers in May to July, while the strap-shaped basal leaves die back as the flower heads open. Give it full sun on a south- or west-facing site with a light, free-draining soil such as loam, sand or chalk; soils should be neutral to alkaline. Bulbs will not tolerate waterlogged ground, so avoid heavy, poorly drained sites where bulbs are liable to rot. The species copes with both exposed and sheltered situations and has a UK hardiness rating of H4–H6 (average to very hardy), making it suitable across much of Britain where winters are not extreme. Use Allium bulgaricum where a summer-flowering bulb is needed in sunny borders, gravel or chalk gardens, or on open banks. Its leaves disappear as the flowers come into bloom, so expect a clear planting site once the heads have finished flowering and the basal foliage has died back.

Growing conditions

Best soil and position for Allium

Sunlight: Full sun
Soil type: Light, free-draining loam, sand or chalk
Soil pH: Neutral to alkaline
Soil moisture: Well drained; bulbs rot in wet ground
Aspect: South or west facing
Exposure: Exposed or sheltered
UK hardiness: H4-H6

Plant details

Allium bulgaricum size, habit and characteristics

Plant type: Bulb
Habit: Upright bare stems from a bulb
Foliage: Deciduous; strap-shaped or grassy basal leaves, dying back as the flowers open
Native to: Bulgaria

Care notes

Pruning and caring for Allium bulgaricum

Cultivation: Plant bulbs in autumn at roughly three times their depth in the sunniest, best-drained ground available; on heavy soil add grit beneath the bulb. Site them behind or among lower perennials, since the foliage yellows and collapses just as the heads open. Leave the leaves to die down completely rather than removing them, and most kinds will bulk up and self-seed steadily.
Pruning: Leave the seedheads standing - they are among the best structural remains in a late-summer border - and cut the stems at the base only once they finally break down.
Propagation: Separate offsets when the bulbs are dormant in late summer. Species come readily from seed but take two to four years to flower, and many self-sow generously.
Pest resistance: Allium leaf miner and onion fly can affect the larger-bulbed kinds; otherwise little troubled.
Disease resistance: White rot and downy mildew occur in wet ground or where alliums have been grown repeatedly on the same site.

Frequently asked questions

How do I grow Allium bulgaricum?

Plant bulbs in autumn at roughly three times their depth in the sunniest, best-drained ground available; on heavy soil add grit beneath the bulb. Site them behind or among lower perennials, since the foliage yellows and collapses just as the heads open. Leave the leaves to die down completely rather than removing them, and most kinds will bulk up and self-seed steadily.

Where is the best place to plant Allium bulgaricum?

Allium bulgaricum prefers full sun. It suits exposed or sheltered positions.

What soil does Allium bulgaricum need?

Allium bulgaricum is adaptable and grows happily in most soil types, including light, free-draining loam and sand or chalk. It prefers neutral to alkaline soil. Aim for soil that stays well drained; bulbs rot in wet ground.

How do I prune Allium bulgaricum?

Leave the seedheads standing - they are among the best structural remains in a late-summer border - and cut the stems at the base only once they finally break down.

Is Allium bulgaricum hardy in the UK?

Allium bulgaricum has an RHS hardiness rating of H4, meaning it is hardy through an average UK winter, tolerating -10 to -5°C.

How do I propagate Allium bulgaricum?

Separate offsets when the bulbs are dormant in late summer. Species come readily from seed but take two to four years to flower, and many self-sow generously.

More in the Allium genus

Browse all Allium →