Delaware Wildflowers • Common names
Canada Thistle
Cirsium arvenseAsteraceae — Aster family
Invasive non-native
White Clay Creek State Park -- Possum Hill
June 2001
Prides Crossing
September 2009
White Clay Creek State Park -- Possum Hill
June 2011
White Clay Creek State Park -- Possum Hill
May 2020
Guide to Cirsium of Delaware
Search Google • Delaware • USDA
Photos copyright David G. Smith
Information from the Delaware Flora Checklist used with author's permission.