When to plant Yarrow in Douglas County, CO
Douglas County's short 121-day growing season means one Yarrow planting between May 22 and June 12. No fall crop in Zone 5b.
When to Plant Yarrow in Douglas County, CO
Achillea millefolium (Yarrow) is a tough, drought-tolerant native perennial with aromatic finely-divided foliage and broad flat-topped flower clusters that serve as a landing platform for hundreds of beneficial insect species. Available in white (the species type) and a wide range of cultivars spanning yellow, gold, pink, salmon, and deep red. Spreads by rhizome to form ground-covering colonies; blooms from late spring through midsummer with reblooming into fall if deadheaded. Exceptional in hot, dry sites where other perennials fail.
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 85°F, 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 Soil Profile
Soil Type
Loam
Soil pH
6.7-8.4
Drainage
Well Drained
Monthly Watering Guide for Yarrow
Yarrow needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Yarrow Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.1" | 0" | ❄️ Dormant |
| Apr | — | 1.3" | 0" | ❄️ Dormant |
| May | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Jun | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Jul | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Aug | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Sep | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Oct | — | 1.1" | 0" | ❄️ Dormant |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 0.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Douglas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yarrow Planting Timeline — Douglas County, CO
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 20 | Mar 20 – Apr 3 |
| Transplant Outdoors | June 5 | Jun 5 – Jun 19 |
| Direct Sow | May 22 | May 22 – Jun 12 |
| Bloom | August 14 | Aug 14 – Nov 27 |
· 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 5.5–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
121 days in Douglas County
Growing Tips for Douglas County
Start seeds indoors 8–10 weeks before last frost; seeds need light for germination — press onto soil surface, do not cover. Direct sow after last frost or divide established clumps in spring or fall. Thrives in poor, well-drained soil — rich soil and high fertility cause floppy stems and reduce flower count. Avoid overwatering; excellent drought tolerance once established. Deadhead spent clusters to encourage rebloom. Divide every 2–3 years to prevent center die-out and control spread. Year 2+ plants bloom most heavily; first-year plants may produce limited flowers. Dried flowers retain color well for arrangements.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Yarrow in Other Locations
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 — 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.
When should I plant Yarrow in Douglas County, CO?
In Douglas County, CO, plant Yarrow after the last frost (around May 22) and before the first frost (around September 20). Best results when soil holds above 50°F.
What growing zone is Douglas County, CO for Yarrow?
Douglas County sits in USDA Zone 5b. Yarrow grows reliably in zones 3a through 9b, so it's a good fit here.
Can Yarrow grow in Douglas County's climate?
Yes — Yarrow grows well in Douglas County's temperate climate. Douglas County averages a 121-day frost-free season, with last frost around May 22 and first frost around September 20.
Your Douglas County Garden Planner — Free
A 22-page printable planner built for Douglas County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.