When to plant Yarrow in Pinal County, AZ
Plant Yarrow in Pinal County, when soil hits 50°F — usually February 9. Continue planting through March 2 for the spring crop.
When to Plant Yarrow in Pinal County, AZ
Your June gardening checklist
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
-
Basket week: yarrow
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
To set up a strong July, 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.
Pinal County, Arizona is in USDA Zone 9a. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.
At an elevation of 3,959 feet, Pinal County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Yarrow may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Yarrow will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Yarrow successfully. Mulch heavily to conserve soil moisture.
Pinal County Soil Profile
Soil Type
Sandy Loam
Soil pH
7-8.6
Drainage
Well Drained
Yarrow 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.
Soil Compatibility in Pinal County
How your county's soil matches Yarrow's growing requirements.
Soil pH
Your soil pH (7.0–8.6) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Pinal County warms quickly in spring but drains fast. Yarrow will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Yarrow.
Organic Matter
Organic matter is low (0.7%). Add 2-3 inches of compost before planting Yarrow.
How to Plant Yarrow
Succession Planting Yarrow
Sow every 6.9 weeks. Last sowing by Aug 29 to harvest before frost.
Yarrow Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Yarrow
Yarrow needs approximately 0.5 inches of water per week (2.2" 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 | 2.2" | 1" | 1.2" | 🚿 Regular watering |
| Mar | 2.2" | 0.8" | 1.4" | 🚿 Regular watering |
| Apr | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| May | 2.2" | 0.3" | 1.9" | 🚿 Regular watering |
| Jun | 2.2" | 0.5" | 1.7" | 🚿 Regular watering |
| Jul | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Oct | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Nov | 2.2" | 0.8" | 1.4" | 🚿 Regular watering |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Pinal County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yarrow Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Yarrow Planting Timeline — Pinal County, AZ
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 29 | Dec 29 – Jan 12 |
| Transplant Outdoors | February 9 | Feb 9 – Feb 23 |
| Direct Sow | February 9 | Feb 9 – Mar 2 |
| Bloom | April 6 | Apr 6 – Aug 24 |
· 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Transplant Outdoors Direct Sow |
| March | Direct Sow |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | Start Indoors |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 5.5–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9a
📆 Growing Season
277 days in Pinal County
Growing Tips for Yarrow in Pinal County
Direct sow Yarrow outdoors after February 23 in Pinal County when soil has warmed and frost danger has passed.
Sandy soil in Pinal County dries quickly — mulch Yarrow with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 98°F in Pinal County, provide afternoon shade for Yarrow and water deeply in the morning.
Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Pinal County receives only 16" of rain annually. Yarrow needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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 Pinal County, AZ?
Pinal County is in Zone 9a with an average last frost of February 23. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pinal County, AZ?
Pinal County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is February 23 and first fall frost is November 27.
When should I plant Yarrow in Pinal County, AZ?
In Pinal County, AZ, plant Yarrow after the last frost (around February 23) and before the first frost (around November 27). Best results when soil holds above 50°F.
What growing zone is Pinal County, AZ for Yarrow?
Pinal County sits in USDA Zone 9a. Yarrow grows reliably in zones 3a through 9b, so it's a good fit here.
Can Yarrow grow in Pinal County's climate?
Yes — Yarrow grows well in Pinal County's temperate climate. Pinal County averages a 278-day frost-free season, with last frost around February 23 and first frost around November 27.
Your Pinal County Garden Planner — Free
A 22-page printable planner built for Pinal County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.