When to Plant Yarrow in Columbia 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.
Columbia County, Washington is in USDA Zone 6b. The average last spring frost is April 28 and the first fall frost is October 11, giving you a growing season of approximately 166 days.
At an elevation of 3,157 feet, Columbia County receives approximately 21.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Yarrow during the growing season.
Columbia County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.5
Drainage
Well Drained
Plant Planting Risk Windows
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
Yarrow Planting Timeline — Columbia County, WA
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Harvest | August 4 | Aug 4 – Oct 20 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
90–120 days
Soil pH
5.5 – 7
USDA Zone
Zone 6b
Growing Season
166 days
Growing Tips for Columbia 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
Yarrow in Other Locations
Frequently Asked Questions
When should I plant Yarrow in Columbia County, WA?
Columbia County is in Zone 6b with an average last frost of April 28. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Columbia County, WA?
Columbia County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is April 28 and first fall frost is October 11.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Columbia County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.