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When to Plant Yarrow in Sangamon 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.

Sangamon County, Illinois is in USDA Zone 5b. The average last spring frost is April 15 and the first fall frost is October 17, giving you a growing season of approximately 185 days.

At an elevation of 1,204 feet, Sangamon County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Yarrow during the growing season.

Sangamon County, IL (Zone 5b) Moderate season
185 days
Last Spring Frost April 15
185 growing days
First Fall Frost October 17

Sangamon County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Transplant: Apr 16 🍅 Harvest: Jul 16 – Oct 1
Recommended (50%) ✓ Fits season (10 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 22 – Oct 7
Safe Start (90%) ✓ Fits season (11 days to spare)
Transplant: May 5 🍅 Harvest: Aug 4 – Oct 20

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Yarrow needs ~1,444 GDD — county provides 2,543 GDD Excellent fit

Yarrow Planting Timeline โ€” Sangamon County, IL

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors April 22 Apr 22 โ€“ May 6
Harvest July 22 Jul 22 โ€“ Oct 7

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 5b

Growing Season

185 days

Growing Tips for Sangamon 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 Sangamon County, IL?

Sangamon County is in Zone 5b with an average last frost of April 15. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sangamon County, IL?

Sangamon County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 15 and first fall frost is October 17.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sangamon County gardeners in Zone 5b 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 Sangamon County, IL. Local conditions may vary. Last updated: April 2026.