Casimir Leek (Allium ampeloprasum) is a striking ornamental member of the allium family, admired for its tall upright foliage and spherical flower heads. Its structural leaves add strong vertical lines to herb patches, mixed borders, and landscape edging, while its round summer blooms draw bees and beneficial pollinators. Durable and easy to grow, it offers both architectural interest and ecological value to sunny garden spaces.
Features
• Tall, upright blue-green foliage for ornamental structure
• Globe-shaped flowers attract pollinators
• Excellent for borders, herb patches, and landscape edging
• Hardy perennial allium for low-maintenance gardens
• Non-GMO Allium ampeloprasum seed variety
Specifications
• Common Name: Casimir Leek
• Scientific Name: Allium ampeloprasum
• Plant Type: Perennial ornamental allium
• USDA Zones: 4–9
• Height: 18–36 inches
• Spread: 8–12 inches
• Growth Habit: Upright clumping foliage
• Foliage: Tall blue-green strap-like leaves
• Flower Color: Round pale-purple or greenish-white heads
• Bloom Season: Mid to late summer
• Heirloom: Yes
• GMO Status: Non-GMO
• Organic: Not certified organic
• Light Requirements: Full sun
• Soil Preference: Well-drained fertile soil
• Water Needs: Moderate
• Pollinator Value: Highly attractive to bees & beneficial insects
• Maintenance Level: Low
• Plant Spacing: 8–12 inches
• Seed Viability: 1–3 years when stored dry & cool
Planting Guide
• Start indoors 8–10 weeks before frost or sow outdoors in spring.
• Cover lightly with 1/8–¼ inch of soil.
• Keep moist until germination (14–30 days).
• Provide full sun and well-drained soil after transplanting.
• Water regularly at establishment, then moderately.
• Leave flower heads to support pollinators and optional self-seeding.
• Divide clumps in future seasons if desired.