When to Plant Alliums in USDA Zone 6b
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.
In Zone 6b, the average last spring frost is around April 3 and the first fall frost is around October 25, giving you a growing season of approximately 205 days.
Alliums Planting Timeline — Zone 6b
Where Is USDA Zone 6b?
The map below highlights the states that contain Zone 6b. Click any state to see the Alliums planting schedule for that location.
Alliums Planting Calendar — Zone 6b
| Activity | When | Date Range |
|---|---|---|
| Bloom | October 11 | Oct 11 – Nov 8 |
| Fall Sowing | September 13 | Sep 13 – Sep 27 |
Plant 5" deep · 7" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | — |
| August | — |
| September | Fall Sowing |
| October | Bloom |
| November | Bloom |
| December | — |
Free Zone 6b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 6b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
Days to Maturity
28–42 days
Soil pH
5.5 – 7.5
Zone Temperature Range
-5°F to 0°F average annual minimum
Growing Season
205 days (Zone 6b average)
Planting Specifications
| Planting Depth | 5 inches |
| Plant Spacing | 7 inches apart |
| Row Spacing | 8 inches between rows |
Succession Planting Alliums in Zone 6b
Sow every 3.1 weeks for continuous harvest throughout the season.
Growing Tips for Alliums in Zone 6b
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.
Companion Planting
Good Companions
Avoid Planting Near
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Saving Alliums Seeds
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Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
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Related Plants
Alliums in Other Zones
Alliums by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- 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 Zone 6b?
In Zone 6b, plan your Alliums planting around the average last frost date of April 3.
Can Alliums grow in Zone 6b?
Yes, Alliums can grow well in Zone 6b, hardy in USDA zones 3a through 9b. Zone 6b has a growing season of approximately 205 days, which is sufficient for Alliums (28-42 days to maturity).
When can I harvest Alliums in Zone 6b?
In Zone 6b, expect to harvest Alliums from October 11 – November 8. Alliums takes 28-42 days from planting to harvest.
What is the last frost date for Zone 6b?
The average last spring frost in Zone 6b is around April 3, and the first fall frost is around October 25. This gives a growing season of approximately 205 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Alliums?
Good companion plants for Alliums include Tulips, Daffodils, Echinacea, Salvia. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 6b Garden Planner — Free
A 22-page printable planner tailored to Zone 6b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.