Allium Medusa

Quick Facts

• Botanical Name: *Allium ‘Medusa’ (PP 28701) 

• Common Name: Ornamental Onion ‘Medusa’

• Hardiness: Zones 4–8 (some sources suggest Zone 3 with proper sites) 

• Mature Size: About 20‑24 in (50‑60 cm) tall and similar spread (~24″) 

• Bloom Time: Mid‑summer into late summer (often July‑August) 

• Flower: Rounded clusters of light amethyst‑purple stars, approx. 2‑in diameter heads. 

• Unique Foliage: Grey‑green, narrow leaves, sometimes twisting–giving nod to its “Medusa” name. 

Light & Site Requirements

• Prefers full sun for best flowering and foliage display.

• Tolerates part sun/partial shade, but performance (flower size, stem length) may be reduced. 

• Choose a site with well‑drained soil; avoid spots that stay soggy. 

Soil, Planting & Spacing

• Soil: Prefers well‑drained, moderately fertile soils; sandy/loamy mixes are beneficial. Especially in heavier soils, improve drainage with grit or sand. 

• Planting Depth/Spacing: Plant bulbs so crown is just at or slightly below soil surface. Space about 20‑24″ apart to allow mature clump spread. 

• In Zone 3: Since hardy to Zone 4, ensure site is well‑drained, maybe on a slight rise or slope to avoid winter wet.

Watering & Maintenance

• Establishment: Water regularly during first season until well anchored.

• Once established: Moderately drought‑tolerant. Avoid over‑watering—bulbs dislike “wet feet.” 

• Deadheading: Remove spent flower heads if desired, though they can also remain for winter interest (seedheads). 

• Division: Clumps may be lifted/divided in either spring or fall if crowded. 

Pests, Problems & Wildlife Interactions

• Pests/Diseases: Generally trouble‑free; watch for onion white rot or downy mildew in overly wet conditions. 

• Wildlife: Excellent deer and rabbit resistance (bulbs taste unappealing to them). Attracts bees and butterflies. 

• Invasiveness: Flowers are sterile (non‑seeding) so minimal risk of self‑sowing and spreading. 

Landscape Uses

• Excellent as a mid‑border accent or in drifts of three or more for visual impact.

• Works well in rock gardens, sunny perennial beds, cut‑flower gardens (flowers make good cut stems).

• Combine with perennials that provide foliage contrast—low profile grasses, sedums, early season perennials that fade when Allium blooms.

Photo from plantaddicts.com