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When to Plant Yarrow in Delaware

Achillea millefolium (Yarrow) is a tough, drought-tolerant native perennial with aromatic finely-divided foliage and broad flat-topped flower clusters that serve as a landing platform for hundreds of beneficial insect species. Available in white (the species type) and a wide range of cultivars spanning yellow, gold, pink, salmon, and deep red. Spreads by rhizome to form ground-covering colonies; blooms from late spring through midsummer with reblooming into fall if deadheaded. Exceptional in hot, dry sites where other perennials fail.

Delaware spans USDA hardiness zones 7b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Click your county for exact Yarrow planting dates based on your local frost dates.

Hover over a county to see details. Click to view planting guide.

Yarrow Planting Calendar for Delaware

Zone 7b ~235 day growing season · Full guide →

Last frost: March 18 · First frost: November 8 · 235 day season

Activity When Date Range
Start Indoors January 14 Jan 14 – Jan 28
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 11 Mar 11 – Apr 1
Bloom May 27 May 27 – Oct 14

Growing Tips for Delaware

Start seeds indoors 8–10 weeks before last frost; seeds need light for germination — press onto soil surface, do not cover. Direct sow after last frost or divide established clumps in spring or fall. Thrives in poor, well-drained soil — rich soil and high fertility cause floppy stems and reduce flower count. Avoid overwatering; excellent drought tolerance once established. Deadhead spent clusters to encourage rebloom. Divide every 2–3 years to prevent center die-out and control spread. Year 2+ plants bloom most heavily; first-year plants may produce limited flowers. Dried flowers retain color well for arrangements.

Frequently Asked Questions

When should I plant Yarrow in Delaware?

Planting dates for Yarrow in Delaware depend on your USDA zone. Delaware spans zones 7b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Delaware for planting?

Delaware contains USDA hardiness zones 7b. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: July 2026.