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When to Plant Yarrow in Skamania 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.

Skamania County, Washington is in USDA Zone 7a. The average last spring frost is April 18 and the first fall frost is October 19, giving you a growing season of approximately 184 days.

At an elevation of 16 feet, Skamania County receives approximately 43 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Yarrow to ensure they mature before fall.

Skamania County, WA (Zone 7a) Moderate season
184 days
Last Spring Frost April 18
184 growing days
First Fall Frost October 19

Skamania County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Transplant: Apr 19 🍅 Harvest: Jul 19 – Oct 4
Recommended (50%) ✓ Fits season (9 days to spare)
Transplant: Apr 25 🍅 Harvest: Jul 25 – Oct 10
Safe Start (90%) ✓ Fits season (17 days to spare)
Transplant: May 17 🍅 Harvest: Aug 16 – Nov 1

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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Yarrow needs ~971 GDD — county provides 1,702 GDD Excellent fit

Yarrow Planting Timeline โ€” Skamania County, WA

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors April 25 Apr 25 โ€“ May 9
Harvest July 25 Jul 25 โ€“ Oct 10

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 Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October Harvest
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 7a

Growing Season

184 days

Growing Tips for Skamania 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 Skamania County, WA?

Skamania County is in Zone 7a with an average last frost of April 18. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Skamania County, WA?

Skamania County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 18 and first fall frost is October 19.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Skamania County gardeners in Zone 7a 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 Skamania County, WA. Local conditions may vary. Last updated: April 2026.