CORVALLIS, Ore. — Annuals live a short, sweet life — they bloom, produce seed and die.
But when allowed to go to seed, annual wildflowers can return each year on their own.
Annual wildflowers support biodiversity and help feed pollinators — including butterflies, native bees and hummingbirds — that sip nectar or gather pollen.
“True wildflower patches will take on a natural, informal appearance in the garden,” said Amy Jo Detweiler, horticulturist with Oregon State University Extension Service. “They will evolve over time and change as the dominant seeds in the mix spread more quickly.”
There is more to establishing wildflowers than scattering seed.
Detweiler recommends:
- Select a sunny site with well-drained soil
- Water soil for several weeks before planting to germinate weed seeds
- Remove weeds by pulling, tilling or using a non-selective herbicide
- Loosen just the top 2 to 4 inches of soil to avoid bringing up weed seed from deeper layers
Gardeners in Central Oregon may need to add organic matter to improve nutrient availability. In Western Oregon, compost can help improve drainage.
Planting windows
Commercial wildflower seed mixes can be planted in spring or fall.
For spring:
- Gently water the site for up to a month before seeding
- Seed in mid April in Western Oregon
- Seed in early May in Central Oregon
- Keep soil lightly watered while seeds germinate if rainfall is limited
For fall:
- Broadcast seed in early November so germination begins in spring
- Leave flower stalks in place long enough to allow seed to drop
Most annual seeds need light to germinate — do not cover them after sowing.
Regional timing considerations
Conditions vary across Oregon and planting windows shift accordingly.
- Southern Oregon — Spring seeding can begin earlier due to faster warm-up (often late March). Fall seeding is especially successful because winter moisture is more reliable.
- Eastern Oregon — plant later in spring (often mid to late May) due to cool nights; fall seeding is successful where winter snow provides moisture protection.
- Oregon Coast — soils stay wet longer; spring seeding is best delayed until soils are workable and not saturated. Fall seeding performs well with winter rains — choose well-drained sites.
Suggestions for annual wildflowers
- Black-eyed Susan (Rudbeckia hirta)
- Blue flax (Linum perenne)
- California poppy (Eschscholzia californica)
- Purple coneflower (Echinacea purpurea)
- Foxglove (Digitalis purpurea)
- Godetia (Clarkia amoena)
- Lance-leaf coreopsis (Coreopsis lanceolata)
- Mountain hollyhock (Iliamna rivularis)
- New England aster (Aster novae-angliae)
- Pot marigold (Calendula officinalis)
- Scarlet gilia (Ipomopsis aggregata)
- Sweet William pinks (Dianthus barbatus)
- White meadowfoam (Limnanthes alba)
- Globe gilia (Gilia capitata)
- Large baby blue eyes (Nemophila menziesii var. atomaria)
Previously titled Wildflowers give gardens a charming, relaxed look
