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When to Plant Yarrow in Douglas County, CO

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.

Douglas County, Colorado is in USDA Zone 5b. The average last spring frost is May 22 and the first fall frost is September 20, giving you a growing season of approximately 121 days.

At an elevation of 7,421 feet, Douglas County receives approximately 12.9 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Yarrow during the growing season. With low rainfall, drip irrigation is essential for growing Yarrow successfully. Mulch heavily to conserve soil moisture.

Douglas County, CO (Zone 5b) Short season
121 days
Last Spring Frost May 22
121 growing days
First Fall Frost September 20

Douglas County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Aug 18 – Nov 3
Recommended (50%) ✗ May not fit
Transplant: May 29 🍅 Harvest: Aug 28 – Nov 13
Safe Start (90%) ✗ May not fit
Transplant: Jun 26 🍅 Harvest: Sep 25 – Dec 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
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 67 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Yarrow needs ~1,444 GDD — county provides 1,663 GDD Good fit

Yarrow Planting Timeline โ€” Douglas County, CO

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors May 29 May 29 โ€“ Jun 12
Harvest August 28 Aug 28 โ€“ Nov 13

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

90โ€“120 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 5b

Growing Season

121 days

Growing Tips for Douglas County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Yarrow in Douglas County, CO?

Douglas County is in Zone 5b with an average last frost of May 22. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Douglas County, CO?

Douglas County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 22 and first fall frost is September 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Douglas County gardeners in Zone 5b 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 Douglas County, CO. Local conditions may vary. Last updated: April 2026.