Anderson's thistle
Cirsium andersonii
Last reviewed: September 2026
Anderson's thistle (Cirsium andersonii) is a biennial forb native to CA, ID, NV, OR. It blooms in July, August, and September. The flowers draw bees, butterflies, and hummingbirds.
Toxicity unknown
Anderson's thistle (Cirsium andersonii) 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
full sun
Water
medium
Size
12"–36" H × 12"–18" W
Bloom
Jul, Aug, Sep
Native to
CA, ID, NV, OR
Pollinators
bees, butterflies, hummingbirds
Before you buy
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A spiny upright thistle with deeply lobed leaves and large rose-red to magenta flower heads in summer. An important nectar source in subalpine meadows and on rocky slopes.
Growing Anderson's thistle
Grow Anderson's thistle in full sun and medium water. Mature plants reach 12 to 36 inches tall and spread 12 to 18 inches wide.
Wildlife value
Flowers are heavily visited by hummingbirds, bees, and butterflies during the summer bloom.
Common questions
- How much sun does Anderson's thistle need?
- Anderson's thistle grows best in full sun conditions.
- When does Anderson's thistle bloom?
- Anderson's thistle blooms in July, August, and September.
- Where is Anderson's thistle native?
- Anderson's thistle (Cirsium andersonii) is native to CA, ID, NV, OR, per the World Checklist of Vascular Plants (Kew).
- What pollinators does Anderson's thistle attract?
- Anderson's thistle draws bees, butterflies, and hummingbirds.
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 Anderson's thistle? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.