The latest skirmish in the BFS’s war on invasive exotic plants took place Saturday, February 4, when 15 hardy volunteers attacked two patches of Italian and Bull Thistles. These two large very spiky purple-flowering thistles are native to Europe, western Asia, and north Africa. The were both introduced to North America accidentally — the Bull Thistle during colonial times and the Italian Thistle in the 1930s. Both compete with and exclude native plants.
Bull Thistle (Cirsium vulgare) growing on the east side of pHake Lake. ©Nancy Hamlett.
Italian Thistle (Carduus pycnocephalus) photographed at an unknown California location. ©Br. Alfred Brousseau.
The two targeted areas were a small patch of mixed Bull and Italian on the east side of pHake Lake and a larger patch of Italian Thistles on the east side of the mound with ‘old’ toad pond. At this time of year, the plants have not formed stalks — only basal rosettes, which we dug out with their tap roots.
Rosettes of Italian Thistles (Carduus pycnocephalus). ©Nancy Hamlett.
The weed diggers in action — Sarah Stevens, Cleo Stannard, Dennis Callaci, Harmonie James, and Dick Haskell digging up Italian thistles by the path to the old toad pond. ©Nancy Hamlett.
A job well done — The thistle diggers with 18 bags of thistles! Left to right: Cleo Stannard, Sarah Stevens, John Robinson, Noah Libeskind, Ben Stapp, Paul Stapp, Dick Haskell, Tim Cox, Elliott Cox, Benjamin Libeskind, Laura Kotovsky, Dennis Callaci, and Harmonie James. ©Nancy Hamlett.
We will be very interested to see next year how much the thistle population has been reduced in these two locations.
More information and resources from the California Invasive Plant Council: