Delaware Wildflowers
Cirsium arvense
(L.) Scop.
Canada Thistle
Asteraceae
— 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