Allium sphaerocephalon f. prostratum Corill., Figureau & Godeau
Allium sphaerocephalon var. purpureum Nyman
Allium tenuiflorum Delastre
Allium veronense Spreng.
Kromon parviflorum (L.) Raf.
Porrum crinitum (Tausch) Rchb.
Porrum descendens (L.) Rchb.
Porrum sphaerocephaluon (L.) Rchb.
Allium sphaerocephalon is a plant species in the
Amaryllis family known as round-headed leek, round-headed garlic, ball-head onion, and other variations on these names. Drumstick allium is another common name applied to this species. Some publications use the alternate spelling Allium sphaerocephalum.[2] It is a
bulbousherbaceousperennial plant.
Allium sphaerocephalon is found in the wild across all parts of Europe except in the northern and western countries (
Scotland,
Ireland,
Netherlands,
Scandinavia, and the
Baltic States).[3][4] Its native range extends to northern Africa and to western Asia as far east as
Iran.[5] It is also reportedly naturalised in
New York State in the United States.[6] In
England it grows wild only in the
Avon Gorge so is known locally as the Bristol onion.[7]
The species is prized by gardeners because of its striking floral display. The spherical "
head" (technically an
umbel) is borne on a long
scape, up to 50 cm in height, usually in July. It can contain hundreds of deep purple flowers.[5]
The
specific epithetsphaerocephalon derives from ancient Greek, meaning "spherical head".
Allium sphaerocephalon produces egg-shaped bulbs. Small
bulblets are present under the outer layer of the stem (making the plant potentially
invasive when grown in gardens). Flowers are borne on a
scape up to 50 cm in height, in a spherical to egg-shaped
umbel, 1–6 cm in diameter, tightly packed with many flowers crowded together. The relatively small size of the umbel relative to the height of the stem makes this one of those described as "drumstick alliums". Individual flowers are reddish-purple and are occasionally replaced by bulbils (again making this a potentially invasive species).[3]
^E.g. Mathew, Brian (1978), The Larger Bulbs, London: B.T. Batsford (in association with the Royal Horticultural Society),
ISBN978-0-7134-1246-8
^
abDavies, Dilys (1992), Alliums : the ornamental onions, London: B.T. Batsford (in association with the Hardy Plant Society),
ISBN978-0-7134-7030-7, p. 135