Wild onion

How to recognise it

Habit

Perennial bulbous plant 30–80 cm tall, with a single straight, stiff stem; often grows in small groups.

Leaf

Round, hollow and tubular, 2–4 mm thick, with a narrow groove on the upper side. The leaves sit on the lower part of the stem, wither by flowering time and smell strongly of garlic.

Flower

A round head 2–5 cm across, at first wrapped in a single short, papery spathe that falls early. It consists mainly of bulbils, with a few pink, purplish or greenish bells on long stalks from June to August, or none, with protruding stamens.

Fruit/Seed

Little seed is produced. The plant spreads mainly by its bulbils, which drop off and soon sprout.

Roots

A small bulb, with several offset bulbs beside it in the soil, some with a hard skin.

Confusion with

Field garlic has two long, tail-like spathes that stick out far above the head. Chives have no bulbils and a dense head full of pink flowers. Young leaves of daffodil or meadow saffron are flat and do not smell of garlic.

Flowering: June–August · Pruning: August

Why grow it?

• A native plant of dykes, verges and dry grassland that does well on poor, sunny ground.
• The flowers, when there are any, are visited by bees, bumblebees and hoverflies.
• A striking, rather quirky head full of bulbils, which sometimes sprout green shoots while still on the stem.
• The young leaves and bulbils taste of garlic and were used in the past like chives or garlic.
• Green in winter: the grassy leaves are there from autumn to spring, when almost everything else is bare.

Wild onion: where does it grow best?

• In the wild on road verges, river and sea dykes, dry limy or sandy grassland, field margins and in the dunes.
• Full sun; in half shade it grows and flowers less.
• Dry to moderately moist, well-drained soil: sand, loam or clay, preferably not too rich.
• In the garden: in a dry flower meadow, a sunny bank, a gravel garden or a low embankment, not in the vegetable patch or lawn.

Goes well with

• Harebell: Delicate blue bells on the same dry, poor soil.
• Cat’s-ear: Yellow flowers all summer for bees on a dry verge.
• Brown knapweed: Purple flower heads for butterflies and bees on a flowery dyke.
• Oxeye daisy: White flowers in June, around the time wild onion flowers.

Wild onion: when and how to plant it?

1. Wild onion is rarely sold; ask a nursery for native plants. Never dig plants up from the wild.
2. Does it already grow nearby? Then it often turns up by itself in a dry strip of grass managed as a poor meadow.
3. Plant bulbils or bulbs in September–October, 3–5 cm deep and 10–15 cm apart, in small groups.
4. Choose a spot where it may spread: in a lawn or among vegetables it soon becomes a stubborn weed.
5. Water once after planting; after that no extra water is needed.

Care

Water

Not needed: it grows in autumn and winter, when there is enough rain, and rests during the dry summer.

Feeding

Don’t. On poor soil it stays in check more easily and more other wild flowers grow alongside it.

Mowing

In a flower meadow: mow in August and, if needed, once more in autumn, always removing the cuttings.

Spreading

Too much of it? In spring, when the leaves are easy to see, dig out the bulbs with all the small offsets. Cut off the heads before they ripen.

Letting bulbils drop

Want more wild onion? Then let the heads ripen on the plant and drop in July–August.

Tip: If you want wild onion in your garden, only put it in a dry flower meadow or bank that you mow once a year, well away from the lawn and vegetable patch: there it is an asset, elsewhere a pest.

Pruning and mowing

Pruning months: August.

When: In August, when the bulbils are ripe and the stems wither.

How:

• Mow or cut the withered stems and remove them along with the cuttings from the flower meadow.
• In a wildlife garden, leave a strip uncut until the following spring: insects overwinter in dry stems and tussocks.
• Want to stop it spreading further? Then cut off the heads in June, before the bulbils ripen.

Caution: Do not throw heads with bulbils on the compost heap: they simply sprout there again.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Bulbils

The easiest method: collect ripe bulbils in July–August and press them 2–3 cm into the soil in autumn. They often sprout that same autumn.

Offsets

When you dig the plant up you find several small bulbs around the main bulb. Replant them in September–October.

Seed

Little is produced and it plays hardly any role in spreading.

Wild onion: how does it get through the winter?

Hardy to −25 °C.

• The grassy, hollow leaves appear in autumn and stay green all winter.
• Fully hardy; in mild weather it simply keeps growing.
• In winter its leaves are among the few fresh green shoots on a verge or dyke.

Diseases and pests

• Weed in lawn or vegetable patch: Thanks to its bulbils and offsets it spreads easily and is hard to get rid of. Dig out the bulbs completely and cut off the heads before they ripen.
• Confusion when foraging: Young leaves of daffodil or meadow saffron are poisonous. They are flat and do not smell of garlic; only pick hollow leaves that clearly smell of garlic.
• Rust: Sometimes small orange spots on the leaves caused by a rust fungus. The plant is hardly affected; no action needed.
• Few flowers: Normal: many heads carry almost nothing but bulbils. That is typical of wild onion, not a disease.

Through the year

• January: Green leaves, even in winter.
• March: Leaves in full growth. Too much? Dig out the bulbs now, while the leaves are easy to see.
• May: Flowering stems grow; the leaves start to wither.
• June: Start of flowering. Bees and hoverflies on the flowers.
• July: Flowers and ripe bulbils. Collect bulbils.
• August: Stems wither: cut or mow them and remove them.
• September: Plant bulbils and offsets.
• October: New leaves appear.
• November: The green leaves keep growing, even in cold weather.

Did you know?

• The species name vineale means ‘of vineyards’: wild onion used to be a well-known weed among the vines.
• Cows that eat a lot of it give garlic-flavoured milk, and grain mixed with the bulbils can taste of garlic too.
• The bulbils sometimes sprout while still in the head, so the stem carries a little wig of green shoots.