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When to Plant Yarrow in Jo Daviess 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.

Jo Daviess County, Illinois is in USDA Zone 5a. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 501 feet, Jo Daviess County receives approximately 35.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Yarrow during the growing season.

Jo Daviess County, IL (Zone 5a) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11

Jo Daviess County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 23 🍅 Harvest: Jul 23 – Oct 8
Recommended (50%) ✗ May not fit
Transplant: May 1 🍅 Harvest: Jul 31 – Oct 16
Safe Start (90%) ✗ May not fit
Transplant: May 16 🍅 Harvest: Aug 15 – Oct 31

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 ~1,601 GDD — county provides 2,592 GDD Excellent fit

Yarrow Planting Timeline โ€” Jo Daviess County, IL

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors May 1 May 1 โ€“ May 15
Harvest July 31 Jul 31 โ€“ Oct 16

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
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

170 days

Growing Tips for Jo Daviess 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 Jo Daviess County, IL?

Jo Daviess County is in Zone 5a with an average last frost of April 24. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jo Daviess County, IL?

Jo Daviess County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 24 and first fall frost is October 11.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jo Daviess 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 Jo Daviess County, IL. Local conditions may vary. Last updated: April 2026.