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When to Plant Yarrow in Marshall County, MN

Marshall County, Minnesota Zone 3b May

Marshall County, Minnesota gardeners: here's your May plan

May is a pivotal month for Marshall County, Minnesota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 11
Avg. first frost October 2
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Transplant yarrow outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

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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.

Marshall County, Minnesota is in USDA Zone 3b. The average last spring frost is May 11 and the first fall frost is October 2, giving you a growing season of approximately 144 days.

At an elevation of 1,303 feet, Marshall County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Yarrow to ensure they mature before fall.

Marshall County, MN (Zone 3b) Short season
144 days
Last Spring Frost May 11
144 growing days
First Fall Frost October 2

Marshall County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Transplant: May 14 🍅 Harvest: Aug 13 – Sep 17
Recommended (50%) ✓ Fits season (11 days to spare)
Transplant: May 18 🍅 Harvest: Aug 17 – Sep 21
Safe Start (90%) ✓ Fits season (11 days to spare)
Transplant: May 30 🍅 Harvest: Aug 29 – Oct 3

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 Marshall County

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

Soil pH

Your soil pH (5.8–7.3) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.

Soil Texture

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

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 4.2" 0" ✅ Rainfall sufficient
Jul 2.2" 3.8" 0" ✅ Rainfall sufficient
Aug 2.2" 3" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 2.6" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Marshall 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 ~1,129 GDD — county provides 1,548 GDD Excellent fit

Yarrow Planting Timeline — Marshall County, MN

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors May 18 May 18 – Jun 1
Harvest August 17 Aug 17 – Sep 21

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August Harvest
September Harvest
October
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 3b

📆 Growing Season

144 days in Marshall County

Growing Tips for Yarrow in Marshall County

Direct sow Yarrow outdoors after May 11 in Marshall 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 Marshall County, MN?

Marshall County is in Zone 3b with an average last frost of May 11. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, MN?

Marshall County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 11 and first fall frost is October 2.

🌱

Your Marshall County Garden Planner — Free

A 24-page printable planner built for Marshall County (Zone 3b). 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 Marshall County, MN. 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.