Rainline Garden
When to plant dahlias in Oregon and Washington
In Portland: Plant dahlia tubers May 10 – Jun 7. In Bend: Jun 9 – Jul 7. Find your city below.
- Difficulty
- Moderate
- Sun
- Full sun
- Spacing
- 18 to 24 inches apart
- Planting depth
- 4 to 6 inches deep, eye pointing up
- Frost
- Killed by frost
- Flowers
- Blooms from midsummer until the first frost
Tubers rot in cold, wet soil, so wait until it warms. West of the Cascades many gardeners leave them in the ground over winter under thick mulch; east of the mountains, dig and store them after the first frost.
Dahlias planting dates by city
| City | Plant in the garden |
|---|---|
| Astoria, OR | May 20 – Jun 17 |
| Baker City, OR | May 25 – Jun 22 |
| Bend and Redmond, OR | Jun 9 – Jul 7 |
| Burns, OR | Jun 11 – Jul 9 |
| Coos Bay and North Bend, OR | May 20 – Jun 17 |
| Eugene, OR | May 10 – Jun 7 |
| Gresham, OR | May 10 – Jun 7 |
| Klamath Falls, OR | Jun 9 – Jul 7 |
| Medford, OR | May 10 – Jun 7 |
| Pendleton, OR | May 1–29 |
| Portland, OR | May 10 – Jun 7 |
| Roseburg, OR | May 10 – Jun 7 |
| Salem, OR | May 10 – Jun 7 |
| The Dalles, OR | May 1–29 |
| Wilsonville and Canby, OR | May 10 – Jun 7 |
| Aberdeen and Hoquiam, WA | May 20 – Jun 17 |
| Bellingham, WA | May 10 – Jun 7 |
| Ellensburg, WA | May 20 – Jun 17 |
| Everett, WA | May 10 – Jun 7 |
| Forks, WA | May 20 – Jun 17 |
| Moses Lake, WA | May 1–29 |
| Olympia, WA | May 10 – Jun 7 |
| Omak and Okanogan, WA | May 20 – Jun 17 |
| Seattle and Tacoma, WA | May 10 – Jun 7 |
| Spokane, WA | May 20 – Jun 17 |
| Tri-Cities (Pasco, Kennewick, Richland), WA | May 1–29 |
| Vancouver, WA | May 10 – Jun 7 |
| Walla Walla, WA | May 1–29 |
| Wenatchee, WA | May 1–29 |
| Yakima, WA | May 8 – Jun 5 |
How to grow dahlias
- Pick a sunny spot with soil that drains well, and mix in an inch or two of compost.
- Plant dahlia tubers on your city's dates, 18 to 24 inches apart. 4 to 6 inches deep, eye pointing up.
- Don't water tubers until shoots appear, then water deeply once a week. Stake tall varieties when you plant so you don't spear the tuber later.
- Harvest: Cut flowers when they're almost fully open, early in the morning. The more you cut, the more they bloom.
Varieties that do well in the Northwest
- Café au Lait
- Bishop of Llandaff
- Cornel Brons
Watch out for
Slugs and earwigs chew young shoots and petals. Use iron phosphate slug bait early in the season.
Sunflowers
Sweet peas
Tulips
Daffodils