Plant of the Week Cirsium pitcheri range map. USDA PLANTS
Database. Cirsium pitcheri leaves. Cirsium pitcheri flower and
seeds. Cirsium pitcheri seed. Bumblebee pollinating a Cirsium
pitcheri. Pitcher’s Thistle (Cirsium pitcheri) By Morty Harwood
Pitcher’s thistle, or dune thistle, occurs along the shores of
Lake Michigan, Huron, and Superior. Originally discovered around
1820 by Dr. Zina Pitcher in what is now Pictured Rocks National
Lakeshore, this small thistle grows to a maximum height of about
three to four feet when flowering, considerably less that the
size reached by its larger cousin Canada thistle (C. arvense). A
native of the Great Lakes dune ecosystem, it thrives in sandy
soil with the help of an impressive taproot (up to six feet
long!) that helps the plant obtain water. For much of its life
the Pitcher’s thistle exists as a small, inconspicuous cluster
of leaves called a rosette, the massive taproot encompassing a
majority of the plants mass. Flowering occurs after the
Pitcher’s thistle survives