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When to Plant Yarrow in Millard County, UT

Millard County, Utah Zone 6a June

Your June planting checklist for Millard County, Utah

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

Avg. last frost May 16
Avg. first frost September 30
Soil temp (4") 50°F
Watering High
Pest pressure High
Daylight 14.7 hrs
July will be here before you know it — start on
  • Starting indoors: 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.

Millard County, Utah is in USDA Zone 6a. The average last spring frost is May 16 and the first fall frost is September 30, giving you a growing season of approximately 137 days.

At an elevation of 6,525 feet, Millard County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 84°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
Millard County, UT (Zone 6a) Short season
137 days
Last Spring Frost May 16
137 growing days
First Fall Frost September 30
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Millard County Soil Profile

Soil Type

Loam

Soil pH

6.5-8

Drainage

Well Drained

Yarrow Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 5 Transplant: May 14 🌸 Bloom: Jul 23 – Nov 12
Recommended (50%) ✗ May not fit
Start indoors: Mar 14 Transplant: May 23 🌸 Bloom: Aug 1 – Nov 21
Safe Start (90%) ✗ May not fit
Start indoors: Apr 7 Transplant: Jun 16 🌸 Bloom: Aug 25 – Dec 15

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 Millard County

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

Soil pH

Your soil pH (6.5–8.0) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Yarrow.

How to Plant Yarrow

18"
Between Plants
24"
Between Rows

Succession Planting Yarrow

2
successive plantings in your 137-day season

Sow every 6.9 weeks. Last sowing by Jul 02 to harvest before frost.

Yarrow Water Budget

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

Water stress score is 8/10 — 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 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 2.2" 2.7" 0" ✅ Rainfall sufficient
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Millard 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 ~975 GDD — county provides 1,781 GDD Excellent fit

Yarrow Planting Timeline — Millard County, UT

Yarrow Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 16 May 16 – Jun 6
Bloom August 1 Aug 1 – Nov 21

· 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 Bloom
December
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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 6a

📆 Growing Season

137 days in Millard County

Growing Tips for Yarrow in Millard County

Direct sow Yarrow outdoors after May 16 in Millard 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.

Millard County receives only 24" of rain annually. Yarrow needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Millard County, UT?

Millard County is in Zone 6a with an average last frost of May 16. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Millard County, UT?

Millard County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 16 and first fall frost is September 30.

🌱

Your Millard County Garden Planner — Free

A 22-page printable planner built for Millard County (Zone 6a). 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 Millard County, UT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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