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When to Plant Yarrow in Marion 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.

Marion County, Illinois is in USDA Zone 6a. The average last spring frost is April 10 and the first fall frost is October 19, giving you a growing season of approximately 192 days.

At an elevation of 964 feet, Marion County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Yarrow during the growing season.

Marion County, IL (Zone 6a) Moderate season
192 days
Last Spring Frost April 10
192 growing days
First Fall Frost October 19

Marion County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Transplant: Apr 12 🍅 Harvest: Jul 12 – Sep 27
Recommended (50%) ✓ Fits season (17 days to spare)
Transplant: Apr 17 🍅 Harvest: Jul 17 – Oct 2
Safe Start (90%) ✓ Fits season (19 days to spare)
Transplant: Apr 27 🍅 Harvest: Jul 27 – Oct 12

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
Yarrow needs ~1,759 GDD — county provides 3,216 GDD Excellent fit

Yarrow Planting Timeline โ€” Marion County, IL

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors April 17 Apr 17 โ€“ May 1
Harvest July 17 Jul 17 โ€“ Oct 2

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 6a

Growing Season

192 days

Growing Tips for Marion 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 Marion County, IL?

Marion County is in Zone 6a with an average last frost of April 10. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Marion County, IL?

Marion County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 10 and first fall frost is October 19.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Marion County gardeners in Zone 6a 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 Marion County, IL. Local conditions may vary. Last updated: April 2026.