Allium sphaerocephalon
Common Name: round-headed leek
Type: Bulb
Family: Amaryllidaceae
Native Range: Europe, northern Africa, western Asia
Zone: 4 to 8
Height: 2.00 to 3.00 feet
Spread: 1.00 to 1.50 feet
Bloom Time: June to July
Bloom Description: Deep green changing to rose purple
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Naturalize
Flower: Showy
Leaf: Colorful, Fragrant
Attracts: Butterflies
Tolerate: Deer, Drought, Black Walnut

Culture

Easily grown in rich, sandy to gritty, dry to medium moisture, well-drained loams in full sun. Plants form dense, slowly-spreading clumps over time. Plants perform best with consistent moisture during the growing season, but tolerate drought after flowering ends. Plant new bulbs 3-5" (3 times bulb width) deep and 4-6" apart in fall. Plants may be grown from seed which is usually sown in fall. Plants will self-seed (sometimes prolifically) in the garden, and if left unchecked will naturalize freely. Deadhead flowers before seed sets to help control any unwanted spread. Bulbs of established plants may be dug, divided and replanted in late summer to early fall after foliage has died down.

Noteworthy Characteristics

Round-headed leak or drumstick allium is a bulbous perennial that is ornamentally grown for its early summer bloom of rose-purple to pink flower heads. This plant is native throughout Europe to the Caucusus, Iran and northern Africa. Cylindrical, hollow, grassy, gray-green leaves to 14" long form a foliage clump in spring. In late spring, sturdy slender flowering stems rise to 24-36" tall topped with egg-shaped flower heads (umbels to 1" wide) in an impressive early summer bloom (June-July in St. Louis). Each flower head is a tight, dense, clover-like cluster of tiny florets that emerge deep green but mature (top to bottom) to rose-purple. Each flower head displays an interesting bi-color effect as the florets change from green to purple. This species blooms later than most of the alliums. Flower heads resemble the flower heads of some clovers. Flowers lack fragrance. Bulbils sometimes form after flowering. Leaves and bulbs have an onion-like aroma when cut or bruised. Synonymous with and formerly known as Allium sphaerocephalum.

Problems

No serious insect or disease problems. Bulb rot may occur in overly moist soils. Mildew, rust, leaf spots and thrips may appear. Plants may colonize over time, but are not considered to be invasive.

Garden Uses

Ornamental onion for rock gardens, beds and borders, cottage gardens, open woodland areas and meadows. Best grown in large groups or massed. May be naturalized. Grows well in containers. Cut flowers are excellent for both fresh cut and dried flower arrangements.