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When to Plant Feverfew in Washington County, IL

Feverfew is a bushy perennial herb with small daisy-like flowers and aromatic leaves. It has been used traditionally for headache relief and is a cheerful garden plant.

Washington County, Illinois is in USDA Zone 6a. The average last spring frost is April 9 and the first fall frost is October 20, giving you a growing season of approximately 194 days.

At an elevation of 1,126 feet, Washington County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Feverfew during the growing season.

Washington County, IL (Zone 6a) Moderate season
194 days
Last Spring Frost April 9
194 growing days
First Fall Frost October 20

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Transplant: Apr 11 🍅 Harvest: Jul 11 – Sep 26
Recommended (50%) ✓ Fits season (19 days to spare)
Transplant: Apr 16 🍅 Harvest: Jul 16 – Oct 1
Safe Start (90%) ✓ Fits season (19 days to spare)
Transplant: Apr 26 🍅 Harvest: Jul 26 – Oct 11

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
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Feverfew needs ~1,601 GDD — county provides 2,958 GDD Excellent fit

Feverfew Planting Timeline โ€” Washington County, IL

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Harvest July 16 Jul 16 โ€“ Oct 1

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 โ€”
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

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

194 days

Growing Tips for Washington County

Start seeds indoors or direct sow on the soil surface. Deadhead regularly to prevent aggressive self-seeding. Divide clumps every 2-3 years to maintain vigor.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Feverfew in Washington County, IL?

Washington County is in Zone 6a with an average last frost of April 9. Plan your Feverfew planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Washington County, IL?

Washington County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 9 and first fall frost is October 20.

๐ŸŒฑ

Plan Your Garden with Confidence

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