Canada thistle is a perennial forb that reproduces by seeds and rhizomes which send up new shoots every 8 to 12 inches. Canada thistle is not just another pretty flower. Severe infestations can reduce wheat yields up to 65% and corn yields by 35%. Canada thistle reduces the carrying capacity of a pasture because cattle avoid the prickly, thistle infested areas.
Found in north central parts of Kansas, Canada thistle is spreading. To avoid infestations in Pratt County, plant weed free seed, use weed free livestock feed, and be sure equipment is cleaned before leaving infested fields. Attention should be paid to any feed or seed imported from northern or northwestern states.
Cultivating a Canada thistle patch will break up the root system and quickly compound the problem unless you intensively cultivate for a whole season.
There are no biological controls approved for use in Canada thistle at this time. Numerous herbicides are available to control and eradicate Canada thistle.
Recommended herbicides are available at the Pratt County Noxious Weed Department on a cost-share basis.