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When to Plant Yarrow in Onslow County, NC

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.

Onslow County, North Carolina is in USDA Zone 8a. The average last spring frost is March 21 and the first fall frost is November 18, giving you a growing season of approximately 242 days.

At an elevation of 541 feet, Onslow County receives approximately 46.8 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90ยฐF, providing good warmth for Yarrow during the growing season. Clay soil retains moisture well for Yarrow, but amend with compost to improve drainage and prevent root rot.

Onslow County, NC (Zone 8a) Long season
242 days
Last Spring Frost March 21
242 growing days
First Fall Frost November 18

Onslow County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (70 days to spare)
Transplant: Mar 18 🍅 Harvest: Jun 17 – Sep 2
Recommended (50%) ✓ Fits season (67 days to spare)
Transplant: Mar 28 🍅 Harvest: Jun 27 – Sep 12
Safe Start (90%) ✓ Fits season (63 days to spare)
Transplant: Apr 15 🍅 Harvest: Jul 15 – Sep 30

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
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Yarrow needs ~1,838 GDD — county provides 4,235 GDD Excellent fit

Yarrow Planting Timeline โ€” Onslow County, NC

Yarrow Planting Calendar

Activity When Date Range
Transplant Outdoors March 28 Mar 28 โ€“ Apr 11
Harvest June 27 Jun 27 โ€“ Sep 12

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 8a

Growing Season

242 days

Growing Tips for Onslow 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 Onslow County, NC?

Onslow County is in Zone 8a with an average last frost of March 21. Plan your Yarrow planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Onslow County, NC?

Onslow County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 21 and first fall frost is November 18.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Onslow County gardeners in Zone 8a 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 Onslow County, NC. Local conditions may vary. Last updated: April 2026.