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When to Plant Yarrow in Carroll County, IL

Yarrow is a drought-tolerant perennial herb with feathery foliage and flat-topped flower clusters in white, yellow, pink, or red. It attracts beneficial insects and is used in herbal medicine.

Carroll County, Illinois is in USDA Zone 5a. The average last spring frost is April 22 and the first fall frost is October 13, giving you a growing season of approximately 174 days.

At an elevation of 778 feet, Carroll County receives approximately 39.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Yarrow to ensure they mature before fall.

Carroll County, IL (Zone 5a) Moderate season
174 days
Last Spring Frost April 22
174 growing days
First Fall Frost October 13

Carroll County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Transplant: Apr 23 🍅 Harvest: Jul 23 – Oct 8
Recommended (50%) ✗ May not fit
Transplant: Apr 29 🍅 Harvest: Jul 29 – Oct 14
Safe Start (90%) ✓ Fits season (2 days to spare)
Transplant: May 10 🍅 Harvest: Aug 9 – Oct 25

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Yarrow needs ~1,365 GDD — county provides 2,262 GDD Excellent fit

Yarrow Planting Timeline โ€” Carroll County, IL

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors April 29 Apr 29 โ€“ May 13
Harvest July 29 Jul 29 โ€“ Oct 14

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

90โ€“120 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 5a

Growing Season

174 days

Growing Tips for Carroll County

Direct sow or start from divisions. Yarrow thrives in poor soil and is very drought-tolerant. Deadhead to encourage reblooming. Divide clumps every 3 years.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Yarrow in Carroll County, IL?

Carroll County is in Zone 5a with an average last frost of April 22. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Carroll County, IL?

Carroll County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 22 and first fall frost is October 13.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Carroll County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Carroll County, IL. Local conditions may vary. Last updated: April 2026.