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When to Plant Yarrow in Nelson County, ND

Nelson County, North Dakota Zone 4a July

Nelson County, North Dakota gardeners: here's your July plan

Each item below is timed to Nelson County, North Dakota's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 12
Avg. first frost September 27
Soil temp (4") 67°F
Watering Low
Pest pressure Moderate
Daylight 15.5 hrs
  1. Get yarrow seeds going inside

    Label every cell. You will absolutely forget which is which otherwise.

August prep starts now
  • First harvests: yarrow

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Achillea millefolium (Yarrow) is a tough, drought-tolerant native perennial with aromatic finely-divided foliage and broad flat-topped flower clusters that serve as a landing platform for hundreds of beneficial insect species. Available in white (the species type) and a wide range of cultivars spanning yellow, gold, pink, salmon, and deep red. Spreads by rhizome to form ground-covering colonies; blooms from late spring through midsummer with reblooming into fall if deadheaded. Exceptional in hot, dry sites where other perennials fail.

Nelson County, North Dakota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 27, giving you a growing season of approximately 138 days.

At an elevation of 547 feet, Nelson County receives approximately 33.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Yarrow to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting Fragrant
Nelson County, ND (Zone 4a) Short season
138 days
Last Spring Frost May 12
138 growing days
First Fall Frost September 27

Nelson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Yarrow Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 27 Transplant: May 22 🌸 Bloom: Aug 7 – Oct 23
Recommended (50%) ✗ May not fit
Start indoors: Mar 3 Transplant: May 26 🌸 Bloom: Aug 11 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: Mar 14 Transplant: Jun 6 🌸 Bloom: Aug 22 – Nov 7

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 Nelson County

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

Soil pH

Your soil pH (6.6–7.8) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Yarrow will thrive.

How to Plant Yarrow

18"
Between Plants
24"
Between Rows

Succession Planting Yarrow

2
successive plantings in your 138-day season

Sow every 6.9 weeks. Last sowing by Jun 29 to harvest before frost.

Yarrow Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 2.2" 4.6" 0" ✅ Rainfall sufficient
Jun 2.2" 5.8" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 4.1" 0" ✅ Rainfall sufficient
Sep 2.2" 3.5" 0" ✅ Rainfall sufficient
Oct 2" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Nelson 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 ~750 GDD — county provides 1,380 GDD Excellent fit

Yarrow Planting Timeline — Nelson County, ND

Yarrow Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 12 May 12 – Jun 2
Bloom August 11 Aug 11 – Oct 27

· 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

138 days in Nelson County

Growing Tips for Yarrow in Nelson County

Direct sow Yarrow outdoors after May 12 in Nelson 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

Start seeds indoors 8–10 weeks before last frost; seeds need light for germination — press onto soil surface, do not cover. Direct sow after last frost or divide established clumps in spring or fall. Thrives in poor, well-drained soil — rich soil and high fertility cause floppy stems and reduce flower count. Avoid overwatering; excellent drought tolerance once established. Deadhead spent clusters to encourage rebloom. Divide every 2–3 years to prevent center die-out and control spread. Year 2+ plants bloom most heavily; first-year plants may produce limited flowers. Dried flowers retain color well for arrangements.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yarrow in Nelson County, ND?

Nelson County is in Zone 4a with an average last frost of May 12. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Nelson County, ND?

Nelson County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 27.

🌱

Your Nelson County Garden Planner — Free

A 22-page printable planner built for Nelson County (Zone 4a). 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 Nelson County, ND. Local conditions may vary. Last updated: July 2026.

Sources & credits

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