Douglas Aster
Symphyotrichum subspicatum
At home in the dense clay that defeats most perennials, 2–4 ft tall; it blooms Aug through Oct.
- Full–part sun
- Average–wet
- 2–4 ft
- Blooms Aug–Oct
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- By state
- California
- Clay soil
California · Zones 5–10
Native Plants for Clay Soil in California
Native plants that root happily into heavy clay — the dense, slow-draining soil that defeats so many garden-center perennials. For California, the right natives are shaped by Coast Ranges, Central Valley & Sierra Nevada and a Mediterranean, summer-dry climate. Every species below, from Douglas Aster and Cardinal Flower to the rest of the list, is genuinely native to California and hardy through zones 5–10. Heavy clay is actually fertile and moisture-holding; the trick is choosing plants whose deep, muscular roots can punch through it and even improve it over time. Avoid working clay when it is wet, plant a little high to keep crowns from sitting in water, and mulch to keep the surface from baking into a crust. These natives do the soil-building for you.
The plants
9 native species for California
Each one native to your region and hardy in zones 5–10 · see this collection in other states.
Cardinal Flower
Lobelia cardinalis
At home in the dense clay that defeats most perennials, 2–4 ft tall; it blooms Jul through Sep.
- Full–part sun
- Average–wet
- 2–4 ft
- Blooms Jul–Sep
Buttonbush
Cephalanthus occidentalis
Roots straight into heavy clay and even improves it, standing 5–10 ft tall, and it blooms Jun through Aug.
- Full–part sun
- Average–wet
- 5–10 ft
- Blooms Jun–Aug
Common Yarrow
Achillea millefolium
A clay-buster — thrives in the slow-draining ground, 1.5–3 ft tall; it blooms May through Aug.
- Full sun
- Dry–average
- 1.5–3 ft
- Blooms May–Aug
Blue Grama
Bouteloua gracilis
A clay-buster — thrives in the slow-draining ground, 8–20 in tall; it blooms Jun through Aug.
- Full sun
- Dry
- 8–20 in
- Blooms Jun–Aug
Sideoats Grama
Bouteloua curtipendula
Roots straight into heavy clay and even improves it, standing 1.5–2.5 ft tall — it flowers in Jun and Jul.
- Full sun
- Dry
- 1.5–2.5 ft
- Blooms Jun–Jul
Red-Twig Dogwood
Cornus sericea
Punches its roots through dense clay where garden-center perennials sulk, at 6–9 ft tall — it flowers in May and Jun.
- Full–part sun
- Average–wet
- 6–9 ft
- Blooms May–Jun
Showy Milkweed
Asclepias speciosa
Roots straight into heavy clay and even improves it, standing 2–4 ft tall; it flowers in Jun and Jul.
- Full sun
- Dry–average
- 2–4 ft
- Blooms Jun–Jul
Little Bluestem
Schizachyrium scoparium
A clay-buster — thrives in the slow-draining ground, 2–4 ft tall.
- Full sun
- Dry–average
- 2–4 ft
- Fall color
Sourcing
Where to find these in California
Seeds & live plants on Amazon
Seed packets, plugs, and starter plants for many of these species ship to your door.
Browse on AmazonSome links here are affiliate links — we may earn a small commission at no extra cost to you. The surest source of locally-adapted stock is a native-plant nursery or a native plant society sale in your area.