When to plant Alliums in Clark County, IL
In Clark County, plant Alliums in spring between mid-spring and late spring, once soil temps hold above 50°F. Clark County's last frost averages April 14, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between September 5 and September 19 — roughly 28–42 days before the first frost on October 17.
When to Plant Alliums in Clark County, IL
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.
Clark County, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 591 feet, Clark County receives approximately 41.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Alliums during the growing season.
Clark County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Alliums Planting Timeline — Clark County, IL
Alliums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Bloom | October 3 | Oct 3 – Oct 31 |
| Fall Sowing | September 5 | Sep 5 – Sep 19 |
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 | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
28–42 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 6b
📆 Growing Season
186 days in Clark County
Growing Tips for Clark County
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
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Alliums in Other Locations
Frequently Asked Questions
When should I plant Alliums in Clark County, IL?
Clark County is in Zone 6b with an average last frost of April 14. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, IL?
Clark County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 17.
When should I plant Alliums in Clark County, IL?
In Clark County, IL, plant Alliums after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Clark County, IL for Alliums?
Clark County sits in USDA Zone 6b. Alliums grows reliably in zones 3a through 9b, so it's a good fit here.
Can Alliums grow in Clark County's climate?
Yes — Alliums grows well in Clark County's temperate climate. Clark County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.
Your Clark County Garden Planner — Free
A 22-page printable planner built for Clark County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.