When to Plant Yarrow in Sheridan County, WY
Your May gardening checklist
Each item below is timed to Sheridan County, Wyoming's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Transplant yarrow outside
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
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.
Sheridan County, Wyoming is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.
At an elevation of 5,266 feet, Sheridan County receives approximately 14.7 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Yarrow to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Yarrow successfully. Mulch heavily to conserve soil moisture.
Sheridan County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.8
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 Sheridan County
How your county's soil matches Yarrow's growing requirements.
Soil pH
Your soil pH (6.6–7.8) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Sheridan County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Yarrow.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Yarrow.
How to Plant Yarrow
Plant Water Budget
Water stress score is 8/10 — 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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.2" | 0" | ❄️ Dormant |
| Apr | — | 1.4" | 0" | ❄️ Dormant |
| May | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Jun | 2.2" | 1" | 1.2" | 🚿 Regular watering |
| Jul | 2.2" | 1.1" | 1.1" | 🚿 Regular watering |
| Aug | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Sep | 2.2" | 1.1" | 1.1" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Sheridan 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 — Sheridan County, WY
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 27 | May 27 – Jun 10 |
| Harvest | August 26 | Aug 26 – Nov 11 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
123 days in Sheridan County
Growing Tips for Yarrow in Sheridan County
Direct sow Yarrow outdoors after May 20 in Sheridan County when soil has warmed and frost danger has passed.
Your 123.0-day growing season in Sheridan County is tight for Yarrow (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Sheridan County receives only 15" of rain annually. Yarrow needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Sheridan County, WY?
Sheridan County is in Zone 5a with an average last frost of May 20. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sheridan County, WY?
Sheridan County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 20.
Your Sheridan County Garden Planner — Free
A 24-page printable planner built for Sheridan County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.