When to plant Yarrow in Trinity County, CA
Aim to plant Yarrow in Trinity County on or after April 5; the window stays open through April 26. Trinity County's 189-day frost-free season gives you enough for a full main crop and a short fall succession.
When to Plant Yarrow in Trinity County, CA
Top priorities for Trinity County, California gardeners in August
If you only do a handful of things in the garden this August, make it these. They're sequenced around your zone's frost timing.
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Start harvesting yarrow
If you can't use it all right away, check the food-preservation section of your planner.
To set up a strong September, finish these tasks
- First harvests: yarrow
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.
Trinity County, California is in USDA Zone 8b. The average last spring frost is April 19 and the first fall frost is October 25, giving you a growing season of approximately 189 days.
At an elevation of 61 feet, Trinity County receives approximately 30.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 79°F, so choose short-season varieties of Yarrow to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Yarrow will need more frequent watering and organic matter to retain nutrients.
Trinity County Soil Profile
Soil Type
Sandy Loam
Soil pH
6-7.1
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 | — | 6.2" | 0" | ❄️ Dormant |
| Feb | — | 6.6" | 0" | ❄️ Dormant |
| Mar | — | 5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| May | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Jun | 4.3" | 0.1" | 4.2" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Oct | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 4.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Trinity County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yarrow Planting Timeline — Trinity County, CA
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 22 | Feb 22 – Mar 8 |
| Transplant Outdoors | April 19 | Apr 19 – May 3 |
| Direct Sow | April 5 | Apr 5 – Apr 26 |
| Bloom | June 21 | Jun 21 – Nov 15 |
· 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | Bloom |
| July | Bloom |
| 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 8b
📆 Growing Season
189 days in Trinity County
Growing Tips for Trinity 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 Trinity County, CA?
Trinity County is in Zone 8b with an average last frost of April 19. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Trinity County, CA?
Trinity County, California is in USDA Hardiness Zone 8b. The average last spring frost is April 19 and first fall frost is October 25.
When should I plant Yarrow in Trinity County, CA?
In Trinity County, CA, plant Yarrow after the last frost (around April 19) and before the first frost (around October 25). Best results when soil holds above 50°F.
What growing zone is Trinity County, CA for Yarrow?
Trinity County sits in USDA Zone 8b. Yarrow grows reliably in zones 3a through 9b, so it's a good fit here.
Can Yarrow grow in Trinity County's climate?
Yes — Yarrow grows well in Trinity County's temperate climate. Trinity County averages a 189-day frost-free season, with last frost around April 19 and first frost around October 25.
Your Trinity County Garden Planner — Free
A 22-page printable planner built for Trinity County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.