When to Plant Alliums in Delaware
Ornamental alliums (Allium spp.) bridge the gap between spring and summer with their striking globe-shaped flower heads in shades of purple, violet, white, and pink. Blooming after tulips have faded, they extend the spring display well into early summer. 'Gladiator', 'Globemaster', and 'Purple Sensation' produce softball-sized heads on 18–36 inch stems, while smaller species create charming accents at border fronts. Deer and rodents shun them completely due to the characteristic onion scent. Dried seed heads provide architectural interest into fall.
Delaware spans USDA hardiness zones 7b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.
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Alliums Planting Calendar for Delaware
▸ Zone 7b ~235 day growing season · Full guide →
Last frost: March 18 · First frost: November 8 · 235 day season
| Activity | When | Date Range |
|---|---|---|
| Bloom | November 1 | Nov 1 – Nov 22 |
| Fall Sowing | October 4 | Oct 4 – Oct 18 |
Growing Tips for Delaware
Plant bulbs in fall, 3–4 times as deep as the bulb diameter (typically 4–6 inches for large types, 3 inches for small species). Space 6–8 inches apart for standard cultivars. Foliage often looks untidy as it dies back before bloom — plant around perennials that will conceal the yellowing leaves. Excellent drainage is essential; alliums rot in wet soils. Leave bulbs in place for naturalization; divide every 3–4 years when clusters become congested. Deadhead spent globes or leave for ornamental seedheads and self-sowing.
Alliums in Other States
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Alliums in Delaware?
Planting dates for Alliums in Delaware depend on your USDA zone. Delaware spans zones 7b. Check the planting calendar above for your specific zone's frost dates and planting windows.
What zone is Delaware for planting?
Delaware contains USDA hardiness zones 7b. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.