Swamp Milkweed
Asclepias incarnata
Roots straight into heavy clay and even improves it, standing 3–4 ft tall, flowering as it flowers in Jul and Aug.
- Full–part sun
- Average–wet
- 3–4 ft
- Blooms Jul–Aug
Colorado · Zones 3–6
Native Plants for Clay Soil in Colorado
Native plants that root happily into heavy clay — the dense, slow-draining soil that defeats so many garden-center perennials. Every species here is genuinely native to Colorado and the wider flora of the Mountain West and hardy through zones 3–6 — proven performers for Colorado's semi-arid, cold winters, high sun climate across Southern Rockies & High Plains, not a generic list. Local standouts include Swamp Milkweed and Common Yarrow. 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
39 native species for Colorado
Each one native to your region and hardy in zones 3–6 · see this collection in other states.
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
Butterfly Weed
Asclepias tuberosa
A clay-buster — thrives in the slow-draining ground, 1.5–2.5 ft tall — it blooms Jun through Aug.
- Full sun
- Dry
- 1.5–2.5 ft
- Blooms Jun–Aug
Golden Alexanders
Zizia aurea
Roots straight into heavy clay and even improves it, standing 1.5–2.5 ft tall, flowering as it blooms Apr through Jun.
- Full–part sun
- Average–wet
- 1.5–2.5 ft
- Blooms Apr–Jun
Wild Bergamot
Monarda fistulosa
A clay-buster — thrives in the slow-draining ground, 2–4 ft tall; it blooms Jun through Aug.
- Full–part sun
- Dry–average
- 2–4 ft
- Blooms Jun–Aug
Serviceberry
Amelanchier canadensis
A clay-buster — thrives in the slow-draining ground, 15–25 ft tall — it flowers in Apr and May.
- Full–part sun
- Average–wet
- 15–25 ft
- Blooms Apr–May
Dense Blazing Star
Liatris spicata
A clay-buster — thrives in the slow-draining ground, 2–4 ft tall, and it flowers in Jul and Aug.
- Full sun
- Average–wet
- 2–4 ft
- Blooms Jul–Aug
Black-Eyed Susan
Rudbeckia hirta
A clay-buster — thrives in the slow-draining ground, 1.5–3 ft tall, and it blooms Jun through Sep.
- Full–part sun
- Dry–average
- 1.5–3 ft
- Blooms Jun–Sep
Aromatic Aster
Symphyotrichum oblongifolium
Punches its roots through dense clay where garden-center perennials sulk, at 1.5–2.5 ft tall; it blooms Sep through Nov.
- Full sun
- Dry
- 1.5–2.5 ft
- Blooms Sep–Nov
New England Aster
Symphyotrichum novae-angliae
Punches its roots through dense clay where garden-center perennials sulk, at 3–5 ft tall; it flowers in Sep and Oct.
- Full–part sun
- Average–wet
- 3–5 ft
- Blooms Sep–Oct
Cup Plant
Silphium perfoliatum
Punches its roots through dense clay where garden-center perennials sulk, at 5–8 ft tall; it blooms Jul through Sep.
- Full–part sun
- Average–wet
- 5–8 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
Maximilian Sunflower
Helianthus maximiliani
A clay-buster — thrives in the slow-draining ground, 5–8 ft tall, flowering as it blooms Aug through Oct.
- Full sun
- Dry–average
- 5–8 ft
- Blooms Aug–Oct
Eastern Redbud
Cercis canadensis
A clay-buster — thrives in the slow-draining ground, 20–30 ft tall, flowering as it flowers in Mar and Apr.
- Full–part sun
- Dry–average
- 20–30 ft
- Blooms Mar–Apr
Foxglove Beardtongue
Penstemon digitalis
Roots straight into heavy clay and even improves it, standing 2–4 ft tall — it flowers in May and Jun.
- Full–part sun
- Dry–average
- 2–4 ft
- Blooms May–Jun
Obedient Plant
Physostegia virginiana
Roots straight into heavy clay and even improves it, standing 2–4 ft tall, flowering as it flowers in Aug and Sep.
- Full–part sun
- Average–wet
- 2–4 ft
- Blooms Aug–Sep
Prairie Blazing Star
Liatris pycnostachya
Roots straight into heavy clay and even improves it, standing 3–5 ft tall, and it flowers in Jul and Aug.
- Full sun
- Dry–average
- 3–5 ft
- Blooms Jul–Aug
Culver's Root
Veronicastrum virginicum
Roots straight into heavy clay and even improves it, standing 3–5 ft tall, flowering as it blooms Jun through Aug.
- Full–part sun
- Average–wet
- 3–5 ft
- Blooms Jun–Aug
Purple Coneflower
Echinacea purpurea
At home in the dense clay that defeats most perennials, 2–4 ft tall, and it blooms Jun through Sep.
- Full–part sun
- Dry–average
- 2–4 ft
- Blooms Jun–Sep
Great Blue Lobelia
Lobelia siphilitica
At home in the dense clay that defeats most perennials, 2–3 ft tall; it flowers in Aug and Sep.
- Full–part sun
- Average–wet
- 2–3 ft
- Blooms Aug–Sep
Spotted Joe-Pye Weed
Eutrochium maculatum
Roots straight into heavy clay and even improves it, standing 4–7 ft tall — it blooms Jul through Sep.
- Full–part sun
- Average–wet
- 4–7 ft
- Blooms Jul–Sep
Red-Twig Dogwood
Cornus sericea
Punches its roots through dense clay where garden-center perennials sulk, at 6–9 ft tall, and it flowers in May and Jun.
- Full–part sun
- Average–wet
- 6–9 ft
- Blooms May–Jun
Rattlesnake Master
Eryngium yuccifolium
A clay-buster — thrives in the slow-draining ground, 3–5 ft tall, flowering as it blooms Jun through Aug.
- Full sun
- Dry–average
- 3–5 ft
- Blooms Jun–Aug
Common Milkweed
Asclepias syriaca
Roots straight into heavy clay and even improves it, standing 3–5 ft tall — it flowers in Jun and Jul.
- Full–part sun
- Dry–average
- 3–5 ft
- Blooms Jun–Jul
15 more also qualify: Virginia Creeper, Ninebark, Sideoats Grama, Stiff Goldenrod, Common Boneset, Showy Milkweed, Blue Vervain, Blue Grama, Fragrant Sumac, American Elderberry, Compass Plant, Little Bluestem, Big Bluestem, Indian Grass, Switchgrass.
Sourcing
Where to find these in Colorado
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.