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When to Plant Yarrow in Marshall County, OK

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.

Marshall County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.

At an elevation of 520 feet, Marshall County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 92ยฐF, providing good warmth for Yarrow during the growing season.

Marshall County, OK (Zone 7b) Long season
233 days
Last Spring Frost March 24
233 growing days
First Fall Frost November 12

Marshall County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (62 days to spare)
Transplant: Mar 18 🍅 Harvest: Jun 17 – Sep 2
Recommended (50%) ✓ Fits season (58 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 30 – Sep 15
Safe Start (90%) ✓ Fits season (55 days to spare)
Transplant: Apr 21 🍅 Harvest: Jul 21 – Oct 6

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.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 554 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Yarrow needs ~1,995 GDD — county provides 4,427 GDD Excellent fit

Yarrow Planting Timeline โ€” Marshall County, OK

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors March 31 Mar 31 โ€“ Apr 14
Harvest June 30 Jun 30 โ€“ Sep 15

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Transplant Outdoors
April Transplant Outdoors
May โ€”
June Harvest
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

90โ€“120 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 7b

Growing Season

233 days

Growing Tips for Marshall County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Yarrow in Marshall County, OK?

Marshall County is in Zone 7b with an average last frost of March 24. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Marshall County, OK?

Marshall County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 24 and first fall frost is November 12.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Marshall County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

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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 Marshall County, OK. Local conditions may vary. Last updated: April 2026.