Canada Thistle Cirsium arvense. This field guide serves as the U.S. Forest Service’s recommendations for management of Canada thistle in forests, woodlands, and rangelands associated with its Southwestern Region. Height to 4 ft. Foliage irregularly and sharply lobed; margins with short spines. Canada thistle is found in annual and perennial crops, rangeland, riparian areas, non-crop areas and industrial sites. Generally, the seeds fall within several meters of the parent plant when dispersed by the pappus. Center for Invasive Species and Ecosystem Health. This may not be effective on dry areas, but it is very effective in the Parkland Ecoregion (De Bruijn, 2004). A habitat conservation area in Regina's Wascana Centre also used goats to control populations of invasive plants (Canada thistle and caragana), which reduced the use of herbicides. It is apparently less common or absent from many areas of southern Illinois, although it could be spreading southward. Root segments as small as 12.5 mm can produce new shoots and become established. The plant does not do well in tight and healthy ecosystems. Habitat: Disturbed areas where Canada thistle is thick. Canada thistle is a state-listed noxious weed in California and many other states. Its leaves have sharp spines along the edges. Canada thistle is best adapted to open areas in temperate regions that satisfy its’ long day requirement for flowering. Alberta Invasive Species Council (Canada). Rob Bourchier, AAFC Lethbridge by e-mail: bourchierR@afr.gc.ca or telephone: (403) 317-2298. However, a single annual mowing can increase populations as a single shoot is replaced by multiple shoots resulting from the loss of apical dominance (Grekul, 2003). Seed is a secondary mode of dispersal. Canada thistle plants produce an average of 1530 seeds per plant, when pollination is successful, and may produce up to 5000 seeds per plant. Canada thistle is found across most of North America. Most of the seeds germinate within one year but can remain viable for up to 20 years if buried deeply. Canada thistle seedlings require open areas with lots of sunlight and little competition in order to establish successfully but, once established, Canada thistle is very competitive and aggressive in spreading through its’ creeping root system. 1963; Wilson and Kachman 1999; Ang et al. It is important to control plants before they regenerate food reserves in their roots or produce seed. Canada thistle thrives in a wide range of soil types but is not tolerant of waterlogged soil or complete shade. Impact on the Canada thistle—the insect does not kill the plant, however, it reduces the plant’s ability to compete and resist pathogens. Provides state, county, point and GIS data. The Canada thistle is a perennial species of flowering plant in the Asteraceae family. Frequent mowing during the growing season can substantially reduce Canada Thistle populations in forage stands, and 3 years of mowing treatments severely reduced Canada Thistle in most studies. The plant is also able to regenerate itself from very small pieces. CultivationWith some exceptions, cultivation has been generally successful at reducing thistle densities, especially in regions with high rainfall. Location in Nebraska. It is a major concern in the Peace River, Omineca and Skeena areas, and is a widespread throughout the province. and Smith) with quackgrass (Elytrigia repens (L.) Neuski. It is able to survive drought conditions due to an extensive creeping root system that commonly reaches depths of 2 to 3 metres and may spread horizontally up to 6 m per year. Starting tillage early in the spring is important, as delaying tillage until thistles were in bloom required two seasons for complete eradication instead of one. Dispersal Dispersal by seed is important in establishment of Canada thistle into new areas, but once established vegetative propagation is the main method of spread. It is native throughout Europe and northern Asia, and widely introduced elsewhere. Noxious Weed Program. Federal Noxious Weed Disseminules of the U.S. - Fact Sheet: Invasive Plant Atlas of the United States - Canada Thistle, Invasive Species Best Control Practices - Canada Thistle (Mar 2018) (PDF | 410 KB), Invasive Plants in Pennsylvania: Canada Thistle (PDF | 576 KB), Natural Resources Series: Range - Canada Thistle, Noxious Weeds of Nebraska - Canada Thistle, Ohio Perennial & Biennial Weed Guide - Canada Thistle, Noxious Weed Information - Canada Thistle, Allelopathic activity of Canada thistle (. It is also commonly known as Canada thistle and field thistle. Cross pollination is necessary for seed production, therefore, both male and female plants must be present at a site for seed production to occur. Weed Science, 29:159-164. The stems above the galls are usually non-productive with abnormal seed heads. USDA. Where it Grows (Habitat & Ecology): Canada thistle is found in annual and perennial crops, rangeland, riparian areas, non-crop areas and industrial sites. Canada thistle is a weed of many crops but is most troublesome in perennial crops and areas where reduced tillage is practiced. The seed germinates best at high temperatures, between 25 and 30 C, where there is high light intensity and from shallow depths (optimum depth for emergence is 1 cm but will emerge from depths up to 6 cm). University of Georgia. Canada thistle, flowers in South Dakota - Photo by Chris Evans; University of Illinois. It may also be found in open canopy woodlands and forests, and upland herbaceous communities. Canada Thistle Cirsium arvense, Canada thistle. Habitat: Canada thistle can be found in disturbed areas with abundant sun and moist but not wet soils. The https:// means all transmitted data is encrypted — in other words, any information or browsing history that you provide is transmitted securely. Canada thistle, Californian thistle, Canadian thistle, creeping thistle, field thistle, corn thistle, perennial thistle, field thistle, Possibly accidental through farm seed shipments. When the larvae chews an exit hole, this introduces an access site for small insects, other arthropods, nematodes and pathogens to the plant. Australian Government. Twenty large national parks across the country report it as a serious invasive plant affecting natural resources. Canada thistle reduces crop yields by competing for light, moisture and nutrients. Habitat Canada thistle is found in any type of habitat but normally establishes quickly in disturbed areas. Department of the Environment and Energy. Canada thistle plants are dioecious; male and female flowers are borne on separate plants. Pennsylvania Department of Conservation and Natural Resources. Rust alone does not usually reduce stands unless combined with stem weevil. It reduces bio-diversity by competing with other species for light, moisture and nutrients and is allelopathic (it produces a toxin that inhibits the growth of other species). The seeds may also be carried long distances in running water, for example streams and irrigation ditches. Impact on the Canada thistle—the insect does not kill the plant, however, by rotting the underground shoot during the winter months reduces shoot production the following spring. Canada thistle (Cirsium arvense) is a perennial that has plagued farmers in America since European settlement, and is a Noxious Weed in Pennsylvania. 1996). Canada thistle seedlings are not very competitive so maintaining healthy, dense vegetative cover will help to prevent establishment of new colonies. Conservation Services Division. It also invades croplands, pastures, lawns, gardens, roadsides, ditches and waste sites. Dense plots of alfalfa (Medicago sativa L.) were reported to reduce Canada Thistle densities from 33 to 11 plants/m2 (Schreiber 1967) and seemed better than grasses at controlling Canada Thistle (Detmers 1927). Rust alone does not usually reduce stands unless combined with stem weevil. ARS. Controlled burning may only damage the above ground portion of the thistle allowing rapid regrowth from the root section or from seed. Hoshovsky (Editors). Washington State Noxious Weed Control Board. One of the most prolific noxious weeds in South Dakota is Canada thistle (Cirsium arvense).In 2018, Canada thistle was officially reported in 57 of South Dakota’s 66 counties with over 185,000 infestations occupying an estimate 1.5 million acres of pasture, range, non-crop, and cropland combined (Figure 1). Canada thistle flourishes where over-grazing, cultivation or mulching has created open habitat for it. See also: Best Control Practice Guides for more guides. Wisconsin Department of Natural Resources. Diet and habitat. Primary mode of spread is creeping roots. Generally, the seeds fall within several meters of the parent plant when dispersed by the pappus. Before sharing sensitive information online, make sure you’re on a .gov or .mil site by inspecting your browser’s address (or “location”) bar. 1961). It can invade sedge meadows and wet prairies from nearby disturbed sites. Provincial Designation: Noxious. Integrated weed management (IWM) considers the overall management of a weed species with the objective of preventing the establishment of the weed from ever occurring, to prevent the spread or to minimize the impact. Canada thistle is an invasive plant that has been listed as a noxious weed in both Arizona and New Mexico. FireControlled burning may only damage the above ground portion of the thistle allowing rapid regrowth from the root section or from seed. Habitat. Weekly cultivation or alternate week cultivation gave about equally good results (Tingey 1934). With some exceptions, cultivation has been generally successful at reducing thistle densities, especially in regions with high rainfall. However, a single annual mowing can increase populations as a single shoot is replaced by multiple shoots resulting from the loss of apical dominance (Grekul, 2003). Michigan Department of Natural Resource; Michigan State University Extension. National Genetic Resources Program. Distribution and habitat in the united states 11. It can occur in wet areas where water levels fluctuate (along stream banks and ditches). Threat. University of Alaska - Anchorage. Wilson RG Jr, 1981b. Chemical and non-chemical thistle control is enhanced when fertilization makes surrounding vegetation more competitive. Minimizing soils disturbances and promptly re-vegetating disturbed areas with competitive plants will also prevent establishment of Canada thistle. 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