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When to Plant Yarrow in Skagit County, WA

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.

Skagit County, Washington is in USDA Zone 8a. The average last spring frost is April 3 and the first fall frost is October 28, giving you a growing season of approximately 208 days.

At an elevation of 232 feet, Skagit County receives approximately 42.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Yarrow during the growing season.

Skagit County, WA (Zone 8a) Long season
208 days
Last Spring Frost April 3
208 growing days
First Fall Frost October 28

Skagit County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (36 days to spare)
Transplant: Mar 30 🍅 Harvest: Jun 29 – Sep 14
Recommended (50%) ✓ Fits season (33 days to spare)
Transplant: Apr 10 🍅 Harvest: Jul 10 – Sep 25
Safe Start (90%) ✓ Fits season (24 days to spare)
Transplant: May 12 🍅 Harvest: Aug 11 – Oct 27

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Yarrow needs ~1,838 GDD — county provides 3,640 GDD Excellent fit

Yarrow Planting Timeline โ€” Skagit County, WA

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Harvest July 10 Jul 10 โ€“ Sep 25

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May โ€”
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
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 8a

Growing Season

208 days

Growing Tips for Skagit 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 Skagit County, WA?

Skagit County is in Zone 8a with an average last frost of April 3. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Skagit County, WA?

Skagit County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 3 and first fall frost is October 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Skagit County gardeners in Zone 8a 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 Skagit County, WA. Local conditions may vary. Last updated: April 2026.