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When to Plant Yarrow in Eau Claire County, WI

Eau Claire County, Wisconsin Zone 4b May

Your May game plan for Eau Claire County, Wisconsin

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Eau Claire County, Wisconsin.

Avg. last frost May 10
Avg. first frost October 3
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Move yarrow into the garden

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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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.

Eau Claire County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 3, giving you a growing season of approximately 146 days.

At an elevation of 674 feet, Eau Claire County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Yarrow to ensure they mature before fall.

Eau Claire County, WI (Zone 4b) Short season
146 days
Last Spring Frost May 10
146 growing days
First Fall Frost October 3

Eau Claire County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 5 🍅 Harvest: Aug 4 – Sep 29
Recommended (50%) ✗ May not fit
Transplant: May 17 🍅 Harvest: Aug 16 – Oct 11
Safe Start (90%) ✓ Fits season (1 days to spare)
Transplant: May 28 🍅 Harvest: Aug 27 – Oct 22

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.

Soil Compatibility in Eau Claire County

How your county's soil matches Yarrow's growing requirements.

Soil pH

Your soil pH (6.2–7.3) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Eau Claire County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Yarrow.

Organic Matter

Organic matter is excellent (4.2%) — Yarrow will thrive.

How to Plant Yarrow

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Yarrow

Yarrow needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Yarrow Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.2" 5.1" 0" ✅ Rainfall sufficient
Jun 2.2" 5.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4.5" 0" ✅ Rainfall sufficient
Aug 2.2" 4.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Eau Claire County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Yarrow Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Yarrow needs ~1,050 GDD — county provides 1,460 GDD Excellent fit

Yarrow Planting Timeline — Eau Claire County, WI

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors May 17 May 17 – May 31
Harvest August 16 Aug 16 – Oct 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

146 days in Eau Claire County

Growing Tips for Yarrow in Eau Claire County

Direct sow Yarrow outdoors after May 10 in Eau Claire County when soil has warmed and frost danger has passed.

Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yarrow in Eau Claire County, WI?

Eau Claire County is in Zone 4b with an average last frost of May 10. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Eau Claire County, WI?

Eau Claire County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 3.

🌱

Your Eau Claire County Garden Planner — Free

A 24-page printable planner built for Eau Claire County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Eau Claire County, WI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.