When to Plant Yarrow in Armstrong County, PA
May to-do list for Armstrong County, Pennsylvania
Your Armstrong County, Pennsylvania garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Get yarrow in the ground
Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.
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.
Armstrong County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 18, giving you a growing season of approximately 172 days.
At an elevation of 213 feet, Armstrong County receives approximately 49.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Yarrow during the growing season.
Armstrong County Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.3
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.
Soil Compatibility in Armstrong County
How your county's soil matches Yarrow's growing requirements.
Soil pH
Your soil pH (5.0–6.3) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Armstrong County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Yarrow.
How to Plant Yarrow
Plant Water Budget
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 | — | 3.6" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 4.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 4.7" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.8" | 0" | ❄️ Dormant |
| Dec | — | 3.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Armstrong 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 — Armstrong County, PA
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 6 | May 6 – May 20 |
| Harvest | August 5 | Aug 5 – Oct 21 |
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
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
172 days in Armstrong County
Growing Tips for Yarrow in Armstrong County
Direct sow Yarrow outdoors after April 29 in Armstrong County when soil has warmed and frost danger has passed.
Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Yarrow in Other Locations
Frequently Asked Questions
When should I plant Yarrow in Armstrong County, PA?
Armstrong County is in Zone 6b with an average last frost of April 29. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Armstrong County, PA?
Armstrong County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 18.
Your Armstrong County Garden Planner — Free
A 24-page printable planner built for Armstrong County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.