Allium senescens subsp. glaucum
Common Name: German garlic
Type: Bulb
Family: Amaryllidaceae
Native Range: Europe, northern Asia
Zone: 4 to 8
Height: 0.50 to 1.00 feet
Spread: 0.50 to 1.00 feet
Bloom Time: July to August
Bloom Description: Lilac to lavender
Sun: Full sun to part shade
Water: Dry to medium
Maintenance: Low
Suggested Use: Ground Cover, Naturalize
Flower: Showy, Fragrant
Leaf: Colorful, Fragrant
Tolerate: Deer, Drought, Black Walnut

Culture

Easily grown in average, dry to medium moisture, well-drained soil in full sun to part shade. Best in full sun, but appreciates some light afternoon shade in hot summer climates. Tolerates a wide range of soils. Tolerates drought. Although this allium is a true bulb (albeit weakly developed) on a rhizome, it forms a clump which can be lifted and divided somewhat easily in either spring or autumn. It will spread in the landscape by short fleshy rhizomes and by self-seeding. Deadheading spent umbels before seed sets not only helps control unwanted spread but also helps build a stronger bloom for the following year.

Noteworthy Characteristics

Allium senescens, commonly known as German garlic or mountain garlic, is an ornamental onion that typically produces 4-9 grass-like, somewhat flattened, broad linear green leaves (1/4” to 1/2” wide) which rise in a dense clump to 6-12” tall. Leaves are semi-evergreen in warm winter climates, but will typically disappear in cool to cold winter climates as soon as fall temperatures dip below 25 degrees F. Hollow, leafless, unbranched, 2-angled or 2-winged flowering scapes rise above the foliage clump in mid-summer to as much as 24” tall, each scape bearing a single terminal globose umbel (to 1” across) of 20-30 tiny pale pink to purple florets. Flowers typically bloom from mid to late summer, sometimes into early fall. German garlic is native to forests, dry stony slopes, steppes, saline meadows and gravelly places from western Europe across northern Asia to Siberia, Mongolia, Manchuria, China and Korea. Although all parts of this plant have an oniony smell and taste when cut or bruised, this species is considered to be an ornamental and is not usually used for culinary purposes.

Genus name comes from the classical Latin name for garlic.

Specific epithet means growing old.

Subsp. glaucum is a more popular garden plant than the species because of its superior ornamental features. It is a glaucous-leaved form that is primarily distinguished from the species by (1) its unusual swirling and twisting glaucous (bluish-gray to gray-green) leaves and (2) its compact size (it is about 1/2 the size of species plants, with foliage rising to about 6” tall). Florets appear in globular clusters (umbels to 1” diameter) which rise above the foliage in mid-summer to 12” tall. Subsp. glaucum typically blooms several weeks earlier than species plants.

Problems

No serious insect or disease problems. Potential diseases include downy mildew, smut and white rot. Onion fly and thrips are occasional insect pests in some areas. Plants may colonize but are not considered to be as invasive as some of the other alliums.

Garden Uses

Rock gardens, border fronts, herb gardens. Good edging plant for gardens or paths. Naturalized areas. Roof gardens. Good cut flower (harvest the stems when about 1/2 of the umbel florets are in open bloom).