Allium, Genus, hollandicum, Species,
- Genus & species
Purple sensation ornamental onion
Overview
Allium hollandicum is a bulbous perennial in the amaryllis family (Amaryllidaceae), producing leafless flowering stems 30–40 inches (75–100 cm) tall from a rounded bulb 1–2 inches (2.5–5 cm) in diameter. Clumps measure 6–10 inches (15–25 cm) wide. Basal leaves are strap-shaped, 12–18 inches (30–45 cm) long and 1–2 inches (2.5–5 cm) wide, gray-green, and begin yellowing at flowering in May, leaving bare stems. Spherical flower heads 4–5 inches (10–12.5 cm) across carry 50–100 star-shaped florets, each 0.5 inch (13 mm) wide, in reddish-purple to violet-purple. Individual heads remain open for 3–4 weeks in May–June, and dried heads persist on stems into summer. The commonly sold selection A. hollandicum 'Purple Sensation' is propagated by bulb offsets, while the species also spreads by seed. Foliage and bulbs carry a mild onion odor when bruised. The yellowing leaves at bloom time leave the base of the stem exposed, and bulbs rot in soil that stays wet in summer dormancy.
Native Range
Allium hollandicum is native to Iran and Central Asia, where it grows on dry, rocky slopes and open steppe at elevations of 3,000–8,000 feet (900–2,400 m). The species name refers to Holland, from where plants were first widely distributed in Europe.Suggested Uses
Used in mixed perennial borders, gravel gardens, and bulb plantings, with groups of 5–10 bulbs spaced 6–8 inches (15–20 cm) apart. Plants rise above low perennials and shrubs in late spring, and bees and hoverflies visit open florets. Bulbs are rarely eaten by deer and rodents.How to Identify
Appearance
Size & Dimensions
Height2'6" - 3'4"
Width/Spread6" - 10"
Colors
Foliage Colors
Bloom Information
Flower heads open in May to early June, with each head remaining colored for 3–4 weeks. Florets open from the outer edge of the sphere inward over 7–10 days. Dried seed heads remain upright and tan through July and are sometimes cut for dried arrangements.
Detailed Descriptions
Flower Description
Reddish-purple to violet-purpleFoliage Description
Gray-greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Bulbs are set 4–6 inches (10–15 cm) deep and 6–8 inches (15–20 cm) apart in fall, in full sun and well-drained soil with a pH of 6.0–7.5. Hardy in USDA zones 4–9. Soil that stays wet during summer dormancy causes bulb rot. Established clumps tolerate dry summers and need no supplemental water after leaves wither. Leaves yellow in May as flowers open, and the foliage is left in place for 4–6 weeks to restock the bulb. Clumps are lifted and divided every 4–5 years if flowering declines. Seed self-sows near parent plants in light soil.Pruning
Flower stems are cut at the base after the heads fade in late June if seed is not wanted. Yellowed foliage is removed once it has fully collapsed, about 4–6 weeks after flowering. Dried seed heads are left in place for winter structure or cut for indoor arrangements.Pruning Schedule
Prune: June–July
summer
Container Growing
Suitable for container growing
Minimum container size: 3 gallons
