perennial onions

Photo: Thomas Pusch — CC BY-SA 4.0 · source

Survives zone 3 through 8

Harvest calendar

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Onion/garlic flavour; leaf and bulb. Welsh onion, chives, ramps.

Hardiness

Zone 3–8

Habit

Herb

Edible part

Leaf

Ripens

Spring–summer

Mature size

Clumping herbs, size depending which you grow: chives 20–30 cm, ramps 15–30 cm, garlic chives 30–50 cm, Welsh onion 40–60 cm. All excellent in containers

Light

Full sun (ramps: shade to partial — spring ephemeral)

Soil pH

6.0–7.0

Environment

Temperate

Native range

A catch-all record for the perennial edible onions rather than one species: chives (Allium schoenoprasum) across the whole northern hemisphere, Welsh onion (A. fistulosum) from China, ramps (A. tricoccum) in eastern North American woodland, and garlic chives (A. tuberosum) from eastern Asia. Check the individual species before siting one — the woodland ramp and the full-sun chive want opposite things.

Status

Both wild and cultivated

Years to fruit

1 yr

Growth speed

Fast — a division makes a full clump in one season

Spacing

20 cm (8 in) apart — about 25 per m² (23 per 10 sq ft)

Leaf shape

Hollow round quills in chives and Welsh onion, flat straps in garlic chives, and broad flat spring blades in ramps. All smell of onion when bruised, which is the safe-identification test that matters: the poisonous look-alikes do not.

Root system

Shallow fibrous roots from a small bulb or a clump of bulbs, almost all of it in the top 15–20 cm. Nothing to compete with a shrub, which is why they slot into gaps and edges so easily; ramps additionally build a deep leaf-litter-fed colony and are slow to recover from digging.

Fruit description

Not grown for fruit — the crop is leaf and bulb. Flowering heads set small dry capsules of hard black seed; the flowers themselves are edible and worth picking for a salad before the seed forms.

Propagation

Division of an established clump is instant and reliable — split it in spring or autumn and replant. Seed works too but is slower, and Allium seed loses viability within a year or two, so sow it fresh.

Pollination

Self-fertile

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.