When to Plant Yarrow in Sanborn County, SD
May in Sanborn County, South Dakota — your action list
Here's what deserves your attention in Sanborn County, South Dakota this month. Everything below is tailored to Zone 5a and timed around your local frost dates.
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Move yarrow from tray to bed
Your last frost (May 2) has passed. These warm-season crops can handle outdoor soil now.
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.
Sanborn County, South Dakota is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 5, giving you a growing season of approximately 156 days.
At an elevation of 860 feet, Sanborn County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Yarrow to ensure they mature before fall.
Sanborn County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.2
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 Sanborn County
How your county's soil matches Yarrow's growing requirements.
Soil pH
Your soil pH (6.7–7.2) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.
Soil Texture
The loam soil in Sanborn County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.0%) — Yarrow will thrive.
How to Plant Yarrow
Plant Water Budget
Water stress score is 6/10 — 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 | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.2" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2" | 0.2" | 💧 Light watering |
| Oct | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Nov | — | 0.7" | 0" | ❄️ Dormant |
| Dec | — | 0.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Sanborn 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 — Sanborn County, SD
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Harvest | August 8 | Aug 8 – Oct 24 |
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 5a
📆 Growing Season
156 days in Sanborn County
Growing Tips for Yarrow in Sanborn County
Direct sow Yarrow outdoors after May 02 in Sanborn 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.
Sanborn County receives only 22" 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 Sanborn County, SD?
Sanborn County is in Zone 5a with an average last frost of May 2. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sanborn County, SD?
Sanborn County, South Dakota is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 5.
Your Sanborn County Garden Planner — Free
A 24-page printable planner built for Sanborn 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.