How much sun does Cotton Thistle need?

Cotton Thistle grows best in full sun conditions.

When does Cotton Thistle bloom?

Cotton Thistle blooms in June, July, and August.

Where is Cotton Thistle native?

Cotton Thistle (Onopordum acanthium) is native to UT, per the USDA PLANTS Database and regional native plant society lists.

What pollinators does Cotton Thistle attract?

Cotton Thistle draws bees, butterflies, and beetles.

Is Cotton Thistle HOA-friendly?

Cotton Thistle takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Cotton Thistle

Name: Pollinator Patch
Author: Pollinator Patch

Onopordum acanthium

Last reviewed: June 2026

Light

full sun

Water

low

Size

36"–72" H × 24"–48" W

Bloom

Jun, Jul, Aug

Native to

Pollinators

bees, butterflies, beetles

Browse plants for this ecoregion

Sierra Nevada Central California Valley Central California Foothills and Coastal Mountains Central Basin and Range Central Oklahoma/Texas Plains

Cotton thistle is a tall, imposing biennial with large, spiny silver-green leaves and purple thistle flowers that bloom through summer. This dramatic plant can reach 6 feet tall and forms a striking architectural presence in the landscape. It self-seeds readily and tolerates drought conditions once established.

In an HOA neighborhood

Cotton Thistle takes more care to keep looking intentional in a front yard. Maintenance level: moderate. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

Extremely tall and can appear weedy
Sharp spines pose safety concerns
Self-seeds aggressively and may spread

Wildlife value

The large purple flowers attract bees, butterflies, and beetles during the summer blooming period. Seeds provide food for finches and other birds in late summer and fall.

Common questions

How much sun does Cotton Thistle need?: Cotton Thistle grows best in full sun conditions.
When does Cotton Thistle bloom?: Cotton Thistle blooms in June, July, and August.
Where is Cotton Thistle native?: Cotton Thistle (Onopordum acanthium) is native to UT, per the USDA PLANTS Database and regional native plant society lists.
What pollinators does Cotton Thistle attract?: Cotton Thistle draws bees, butterflies, and beetles.
Is Cotton Thistle HOA-friendly?: Cotton Thistle takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

Ready to grow Cotton Thistle? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

Add this plant to your garden

iPhone app Android app

Not sure where to start? Take the 2-minute yard quiz