Bristol onion or round-headed leek

Scientific name: Allium sphaerocephalon

Status: Nationally rare.  IUCN – Vulnerable.  Also a protected plant (under Schedule 8 of Wildlife & Countryside Act 1981).

Flowering time: June – August

Description: Distinctive ball of magenta flowers produced on a tall stem. Gardeners know these plants as ‘drumsticks’ because of their flower shape. The ‘sphaerocephalon’ part of this plant’s scientific name means ’round-headed’.

Social history: The Bristol onion featured on a set of rare plant stamps issued by Royal Mail in 2009.

Taxonomy: A member of the Allium genus, which includes leeks, onions, garlic and chives.

Global and national distribution: The Avon Gorge is the only place where this plant grows wild in the UK. Also found in Jersey, it is widely distributed throughout southern Europe.

Threats: Two isolated populations on the Bristol side of the Avon Gorge. Loss of open habitat from scrub and tree encroachment. Susceptible to onion rust fungus.

Photographs: © Denice Stout, © Phil Jearey.