Annual Flower

When to Plant Sunflowers in Washington

Few things bring more joy than a row of sunflowers turning their faces to the sun. Easy, dramatic, and pollinator-friendly.

The Short Answer

Sunflowers grow well on both sides of Washington's Cascades, with eastern Washington's hot, sunny conditions producing the most impressive results. Western Washington sunflowers are achievable — the crop needs less heat than tomatoes — but blooms may be smaller and later.

Washington Frost Dates

Your planting dates depend on which part of Washington you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Western Washington (Seattle/Tacoma) 8a, 8b Mar 25 - Apr 15 Oct 25 - Nov 15
Puget Sound 8b, 9a Mar 15 - Apr 5 Nov 1 - Nov 20
Eastern Washington 5b, 6a, 6b, 7a Apr 25 - May 15 Sep 25 - Oct 15
Central Washington 6a, 6b, 7a Apr 20 - May 10 Oct 1 - Oct 20

Sunflowers Planting Schedule for Washington

Western Washington (Seattle/Tacoma) (Zones 8a, 8b)

Average last frost: Mar 25 - Apr 15 · Average first frost: Oct 25 - Nov 15

Start Seeds Indoors
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Puget Sound (Zones 8b, 9a)

Average last frost: Mar 15 - Apr 5 · Average first frost: Nov 1 - Nov 20

Start Seeds Indoors
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Eastern Washington (Zones 5b, 6a, 6b, 7a)

Average last frost: Apr 25 - May 15 · Average first frost: Sep 25 - Oct 15

Start Seeds Indoors
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Central Washington (Zones 6a, 6b, 7a)

Average last frost: Apr 20 - May 10 · Average first frost: Oct 1 - Oct 20

Start Seeds Indoors
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Growing Sunflowers in Washington

State-Specific Growing Tips

Western WA: sow from late May. Sunflowers grow decently in the Puget Sound region — they're less heat-demanding than most people assume. Eastern WA: sow from mid-May. Hot sun and irrigation produce impressive sunflowers. WSU Extension includes sunflowers in pollinator garden recommendations.

Recommended Varieties for Washington

Western WA: choose shorter varieties (Teddy Bear, Music Box, Sunspot) and early types that bloom before fall rain. Eastern WA: any variety thrives — Mammoth, ProCut, Sunrich all do well.

Common Challenges in Washington

Western WA: late-summer rain can damage flower heads. Slugs on seedlings. Eastern WA: minimal issues in the dry climate. Birds eat seeds in both regions.

Growing Tips

Direct sow is preferred — sunflowers don't love transplanting. Succession plant every 2 weeks for blooms all summer.

Companion Planting

Plant sunflowers alongside these companions for better growth:

Cucumbers Squash Corn

Keep sunflowers away from:

Potatoes

The Bottom Line

Sunflowers can be grown successfully in Washington with proper attention to regional frost dates and local growing conditions. Timing varies across the state — Western Washington (Seattle/Tacoma) gardeners work with a last frost around Mar 25 - Apr 15, while Central Washington sees frost end around Apr 20 - May 10. Choose varieties suited to your region, amend your soil based on its specific needs, and monitor for the pests and diseases most common in your area. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Sunflowers Growing Guide National planting guide with all states Washington Planting Calendar All plants for Washington Sunflowers in Alabama Alabama planting dates Sunflowers in Alaska Alaska planting dates Sunflowers in Arizona Arizona planting dates Sunflowers in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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