When to Plant Yarrow in Costilla 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.
Costilla County, Colorado is in USDA Zone 5a. The average last spring frost is June 8 and the first fall frost is September 16, giving you a growing season of approximately 100 days.
At an elevation of 5,598 feet, Costilla County receives approximately 21 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Yarrow during the growing season.
Costilla County Soil Profile
Soil Type
Loam
Soil pH
6.2-8.3
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
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Yarrow Planting Timeline — Costilla County, CO
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 15 | Jun 15 – Jun 29 |
| Harvest | September 14 | Sep 14 – Nov 30 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| 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 5a
Growing Season
100 days
Growing Tips for Costilla 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 Costilla County, CO?
Costilla County is in Zone 5a with an average last frost of June 8. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Costilla County, CO?
Costilla County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 8 and first fall frost is September 16.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Costilla County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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