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When to Plant Yarrow in Lyman County, SD

Lyman County, South Dakota Zone 4a April

April in the garden — Lyman County, South Dakota

We've pulled the most time-sensitive tasks for Lyman County, South Dakota this April and put them front and centre. Tackle them in order.

Avg. last frost May 7
Avg. first frost October 6
Soil temp (4") 40°F
Watering Moderate
Pest pressure Low
Daylight 13.2 hrs
Get ahead of May
  • Transplants going out: yarrow

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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.

Lyman County, South Dakota is in USDA Zone 4a. The average last spring frost is May 7 and the first fall frost is October 6, giving you a growing season of approximately 152 days.

At an elevation of 1,055 feet, Lyman County receives approximately 29.3 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.

Lyman County, SD (Zone 4a) Moderate season
152 days
Last Spring Frost May 7
152 growing days
First Fall Frost October 6
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Lyman County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: May 7 🍅 Harvest: Aug 6 – Oct 1
Recommended (50%) ✗ May not fit
Transplant: May 14 🍅 Harvest: Aug 13 – Oct 8
Safe Start (90%) ✓ Fits season (3 days to spare)
Transplant: May 26 🍅 Harvest: Aug 25 – Oct 20

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 Lyman County

How your county's soil matches Yarrow's growing requirements.

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Lyman County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Yarrow.

How to Plant Yarrow

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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 0.8" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 2.2" 4.1" 0" ✅ Rainfall sufficient
Jun 2.2" 4.8" 0" ✅ Rainfall sufficient
Jul 2.2" 3.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 1.8" 0.4" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Lyman 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 needs ~1,208 GDD — county provides 1,748 GDD Excellent fit

Yarrow Planting Timeline — Lyman County, SD

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 – May 28
Harvest August 13 Aug 13 – Oct 8

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August Harvest
September Harvest
October Harvest
November
December
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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: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

152 days in Lyman County

Growing Tips for Yarrow in Lyman County

Direct sow Yarrow outdoors after May 07 in Lyman 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 →

Frequently Asked Questions

When should I plant Yarrow in Lyman County, SD?

Lyman County is in Zone 4a with an average last frost of May 7. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lyman County, SD?

Lyman County, South Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 7 and first fall frost is October 6.

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Your Lyman County Garden Planner — Free

A 24-page printable planner built for Lyman County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lyman County, SD. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.