Dunce-nettle
Cirsium muticum
Last reviewed: September 2026
Dunce-nettle (Cirsium muticum) is a wetland forb that blooms from July through September, producing purple flower heads favored by bees and butterflies in wet meadows, marshes, and swamp edges.
Toxicity unknown
Dunce-nettle (Cirsium muticum) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
part sun
Water
medium
Size
24"–60" H × 12"–24" W
Bloom
Jul, Aug, Sep
Native to
AL, AR, CT, DE and 29 more states
Pollinators
bees, butterflies
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.
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Swamp thistle is a tall native perennial that produces clusters of pink to purple flowers from summer through early fall. Despite its common name, it's not aggressive like non-native thistles and provides excellent wildlife value in naturalized settings.
Growing Dunce-nettle
Grow Dunce-nettle in part sun and medium water. Mature plants reach 24 to 60 inches tall and spread 12 to 24 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Dunce-nettle takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Thistle appearance triggers negative associations
- Can reach 5 feet tall
- Dies back completely in winter leaving bare stems
Wildlife value
The flowers are magnets for native bees, butterflies, and other pollinators during late summer blooms. Seeds provide food for goldfinches and other birds in fall.
Common questions
- When does Dunce-nettle bloom?
- Cirsium muticum typically flowers from July through September, with rounded purple blooms appearing atop tall, unbranched stems.
- What pollinators visit Dunce-nettle?
- Bees and butterflies are the main visitors to Cirsium muticum, drawn to its nectar-rich purple flower heads during the summer bloom period.
- What growing conditions does Dunce-nettle prefer?
- This plant does best in consistently moist to wet soil and part sun to part shade, often found in wet meadows, fens, and swamp margins.
- How much sun does Dunce-nettle need?
- Cirsium muticum grows well with part sun to part shade, tolerating dappled light conditions typical of wooded wetland edges.
- Is Dunce-nettle HOA-friendly?
- Dunce-nettle takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.
Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
If something looks wrong
Common plant problems, and what to check first
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow Dunce-nettle? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
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