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A tall sunflower in bloom against a blue sky
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When to plant sunflowers in Leavenworth, WA

Plant sunflowers from seed, directly in the garden in Leavenworth, May 17 – Jun 28.

Easy Plant seeds in the ground

Why these dates

Leavenworth's typical last spring frost is May 10. Frost kills sunflowers, so planting starts once frost risk drops, around May 17. Keep row cover or a frost blanket handy for the first couple of weeks, since a late frost is still possible.

Inland Northwest. Higher, colder interior valleys. Cold springs and an earlier fall mean a shorter season; quick-maturing varieties pay off.

Difficulty
Easy
Sun
Full sun
Spacing
6 inches (small types) to 24 inches (giants) apart
Planting depth
1 inch deep
Frost
Killed by frost
Flowers
Blooms about 60 to 90 days after sowing

Step by step

  1. Prepare the bed: loosen the soil and mix in an inch or two of compost.
  2. Plant seeds May 17 – Jun 28, 1 inch deep, 6 inches (small types) to 24 inches (giants) apart.
  3. Keep the soil evenly moist until sprouts appear, which can take one to three weeks in cool soil.
  4. Harvest: Cut flowers when the petals are just opening. For seeds, let heads dry on the plant until the back turns brown, and cover them from birds.

Varieties that do well here

  • Mammoth Grey Stripe (giant)
  • ProCut (for cutting)
  • Teddy Bear (dwarf)

Watch out for

Birds and slugs eat seedlings. Cover the seedbed until plants are a few inches tall.

Sow them where they'll grow; they dislike transplanting. Tall varieties need a spot out of the wind.

Common questions

When is the last frost in Leavenworth, WA?

Typically May 10. In 9 years out of 10, frost is over by May 28. These are 1991–2020 NOAA climate normals for Leavenworth.

Is it too late to plant sunflowers in Leavenworth?

The spring planting window runs through June 28. Later plantings may not have time to bloom well before the first fall frost, which usually arrives around September 30.

When do sunflowers bloom?

Blooms about 60 to 90 days after sowing. Cut flowers when the petals are just opening. For seeds, let heads dry on the plant until the back turns brown, and cover them from birds.

Also plant in Leavenworth around the same time

Planting dates for sunflowers in nearby areas

Full planting calendar for Leavenworth · Sunflowers in every city