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Allium 'Globemaster'
globemaster onion
Hybrid of garden origin — parent species from Iran, Turkey, and Central AsiaLearn more
Overview
Allium 'Globemaster' is Globemaster allium (giant allium), a bulbous perennial growing 30-36 inches (75-90 cm) tall and 12-18 inches (30-45 cm) wide. Deep violet to pinkish-purple star-shaped florets 0.5 inch (1.3 cm) packed into dense spherical umbels 6-10 inches (15-25 cm) in diameter on stiff upright stalks in May-July (5 weeks). Blue-green strap-like basal leaves 12-18 inches (30-45 cm). The foliage yellows and withers before or during flowering — this dying foliage at bloom time is the primary aesthetic limitation; plant among later-emerging perennials or grasses to conceal. A sterile hybrid (likely A. macleanii × A. christophii) — does not self-sow. The dried seed heads hold their spherical form through summer and fall. In Amaryllidaceae. Plant bulbs 6-8 inches (15-20 cm) deep in fall. Requires well-drained soil — bulb rot in wet winter conditions. The onion-like scent when foliage is crushed deters deer and rabbits. Moderately fragrant flowers. Toxic to cats and dogs (thiosulfates — causes hemolytic anemia). Zones 4-8. Full sun. Growth rate is moderate.
Native Range
Hybrid of garden origin — parent species from Iran, Turkey, and Central Asia.Suggested Uses
Grown in mixed borders, perennial beds, and in containers of at least 5 gallons (19 L), spaced 12-18 inches (30-45 cm). Plant among companion perennials that conceal dying foliage. Dried seed heads for winter structure. Deer-resistant. Toxic to pets. Zones 4-8.How to Identify
Appearance
Size & Dimensions
Height2'6" - 3'
Width/Spread1' - 1'6"
Reaches mature size in approximately 3 years
Colors
Bloom Information
Late spring to early summer (May-July). Deep violet to pinkish-purple florets in dense spherical umbels 6-10 inches (15-25 cm). 5 weeks. Bee- and butterfly-visited. Dried seed heads persist. Sterile — no viable seed.Detailed Descriptions
Flower Description
Deep violet to pinkish-purple, star-shaped individual florets 0.5 inch (1.3 cm) packed into dense spherical umbels 6-10 inches (15-25 cm) in diameterFoliage Description
Blue-green, strap-like, basal, 12-18 inches (30-45 cm) long and 2-3 inches (5-7 cm) wide; dies back before or during flowering — the foliage yellows and withers as the flower stalk emergesGrowing Conditions
Sun Requirements
Requires 6-12 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
Full sun (6+ hours). Well-drained soil pH 6.5-7.5 — bulb rot in wet winter soil. Plant 6-8 inches (15-20 cm) deep in fall. Drought-tolerant once dormant. Dying foliage at bloom time — conceal with companion plants. Cut or leave dried seed heads. Toxic to cats and dogs. Deer-resistant. Zones 4-8.Pruning
Cut spent flower stalks at ground level after bloom or leave dried seed heads for structural interest. Allow foliage to yellow and wither naturally (feeds the bulb for next year's bloom) — do not cut green foliage.Pruning Schedule
J
F
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summer
Maintenance Level
lowContainer Growing
✓ Suitable for container growing
Minimum container size: 5 gallons
⚠️ Toxicity Warning
Toxic to petsPlanting Guide
Planting Methods & Timing
Planting Method
transplant