Allium triquetrum aka Three Cornered Leek

Allium triquetrum is a bulbous perennial called three-cornered leek or garlic. It belongs to the amaryllis family, Amaryllidaceae. Its native range includes southern Europe and parts of North Africa. Records cover France, Spain, Italy, Algeria, Morocco and Tunisia. It has also become established in southwest England. Damp hedge banks and waste ground provide habitat for this plant.

Clumps have narrow green leaves and upright, three-sided flower stalks. The leaves die back each year. Stalks reach about 1.5 feet [0.45 m] tall. The RHS gives an upper garden height of 1.6 feet [0.5 m]. Its listed spread also reaches 1.6 feet [0.5 m]. Chicago Botanic Garden gives a shorter height of 1 foot [0.3 m]. Plants take two to five years to reach full size.

White flowers appear from spring into early summer. Chicago Botanic Garden lists May to June as its bloom season. Each petal has a green stripe down its centre. The flowers form rounded umbels about the size of golf balls. Plants spread through both seeds and bulbils. This spread matters more than their small size might suggest. The RHS lists this species as invasive in Great Britain. Schedule 9 makes planting it in the wild an offence there. Causing it to grow in the wild is also illegal. The law does not ban its sale.

It grows in full sun or part shade. Chicago Botanic Garden favours part shade and moist, well-drained loam. The RHS also lists chalk, clay and sandy soils as suitable. It accepts acid, neutral and alkaline soil. A sheltered site suits its stated growing needs. Water needs are moderate, with moist soil that drains well. The RHS rates its UK hardiness as H5. Chicago Botanic Garden lists USDA zones 5–9. Woodland edges and hedgerows are listed garden settings. Its invasive status limits where planting is appropriate.

The bulbs, leaves and flowers have food uses. Small bulbs have a mild garlic taste, raw or cooked. Young leaves suit salads; older leaves can flavour cooked dishes. Raw flowers serve as an edible garnish. Leaves remain available from late autumn through spring. Bulbs can be harvested in early summer after growth dies down. PFAF reports moth-repellent use for the plant's juice. Its safety note concerns poisoning reports from other alliums, not this species. It gives no confirmed poisoning report for Allium triquetrum itself.