These prickles are an adaptation that protects the plant from being eaten by herbivores. Once it’s here efforts to stop them aren’t usually that effective (sometimes biological controls will work). In non-cropland ecosystems, Canada thistle can crowd out and replace native grasses and forbs limiting land’s recreational use. If treated properly and in a timely manner using medication and intravenous … Both natural and human caused disturbances can create the opportunity for Canada thistle to become established in natural communities.”, Ohio: So Meyer is hoping a little education will help people distinguish between good and bad thistles with pinkish-purple flowers. This list includes tansy ragwort, yellow starthistle, Russian knapweed, Canada thistle (Cirsium arvense), poison hemlocks, field bindweed, houndstongue, Scotchbroom (Cytisus scoparius), horsetails, leafy spurge, black henbane (Hyoscyamus niger), Klamath weed or St. Johnswort, kochia, yellow toadflax or butter-and-eggs (Linaria vulgaris), silverleaf nightshade (Solanum elaeagnifolium), and puncture vine.”, Colorado: “Canada thistle (Cirsium arvense) is an aggressive, creeping perennial weed that infests crops, pastures, rangeland, roadsides and noncrop areas. Reach the writer at 402-473-7250 or nhicks@journalstar.com. Jimsonweed and poison ivy are native and on many state lists. I think you’ll find that the answer is emerging weed problems rather than weeds which have been here for almost 400 years. Musk thistle flowers in May and June in the eastern part of the state. There was a problem saving your notification. because of their invasive nature.”. It is known to harbor other pest species, e.g., insects, and has long been recognized as an agricultural est. “By 1795, Vermont enacted noxious weed legislation against Canada thistle and, in the early 1900’s, the currently named Noxious Weed Act gave a person the right to eradicate this species wherever they found it without fear of trespassing. Many states list more than a hundred noxious weeds and others only list a few. Additionally, plants can spread by growing in circular … Most people see it as an aggressive weed, and they have no idea it has many useful treats for homesteaders and preppers alike. This time of the year the blooming plant is likely tall thistle, a good thistle, a native thistle. Books: http://www.sustainablelandscapesandgardens.com Canada thistle invades natural areas such as prairies, savannas, open areas in forests, and dunes if some degree of disturbance already exists. The plant is beneficial for pollinators that rely on nectar. “PROBLEM: The extensive root system of Canada thistle allows it to out-compete and displace many native species, especially in degraded prairies where native species are not well established. One morning this month the county’s weed superintendent got a call from a golfer who said he'd spotted musk thistle, the noxious weed with the pinkish purple flower, near the sixth fairway at HiMark Golf Course. Sorry, Jeff. (* about $6500 of my annual salary and benefits comes from fulfilling Master Gardener responsibilities. Enter your email address to subscribe to this blog and receive notifications of new posts by email. ), From the Minnesota pdf referenced above: One reference points out that Canadian thistle is toxic to horses — that’s wrong. Tall thistle is generally no taller than musk thistle -- 5 to 7 feet tall. Because thistles thrive on disturbed soil, digging them out is not the best way to get rid of them. Kentucky: At this time of year perennial weeds begin moving carbohydrates f…, Fall’s cooler temperatures, increased moisture and reduced humidity allow properly planted trees to establish their root systems quickly, givi…, For decades, Lincoln city parks were turf and trees. In Canada and the U.S., it is considered one of the most tenacious and economically important agricultural weeds, but only in recent years has it been recognized as a problem in natural areas. Canada thistle is a perennial plant with an extensive horizontal and vertical rhizome and root system, which can spread 15′ wide and 6-15′ deep. “The state regulations of the Kentucky Seed Law classify certain plants such as Canada thistle, johnsongrass, and quackgrass as noxious weeds and prohibit their presence in commercial seed sold in Kentucky.”, National Park Service: So here’s Ray: Here is a brief summary of the results of a google search of .edu and .gov or .us sites on the subject of Canada thistle or Cirsium arvense as a noxious weed, examining the “whys” by a mostly volunteer* Master Gardener reliant on published literature by reputable sources and charged with fulfilling the Land Grant University charter to bring science based information to the local level. Of the 11 on the Minnesota list, can you rank them, and tell us why or why not they should be on there? Considered noxious under the BC Weed Control Act, Canada thistle is commonly found on roadsides, cultivated fields, pastures, logged forests, riverbanks, and other disturbed areas. It is a major concern in the Peace … Controlling Canada thistle organically is done with a sharp eye and an even sharper pair of scissors. 1993). Bob Rodgers at Survivopedia has an article on Why You Need to Use Thistle for Food and Medicine. If Dr. Chalker-Scott can use noxious weed lists as a standard against which to judge permaculture practices, on what basis should folks like me be more or less cavalier about them? “Threats: Canada thistle’s rapid growth aggressively competes with native plants and crops for nutrients, moisture and light. Cirsium arvense threatens natural communities by directly competing with and displacing native vegetation, decreasing species diversity, and changing the structure and composition of some habitats. It is adapted to a wide range of soil conditions, and spreads vigorously by wind-borne seeds and by way of its extensive, creeping root system. Canada thistle (Cirsium arvense) is a perennial that has plagued farmers in America since European settlement, and is a Noxious Weed in Pennsylvania. I’ll leave cannabis out the discussion, for obvious reasons, but I don’t think it should be “up to me” to decide these things. Click to share on Facebook (Opens in new window), Click to share on Twitter (Opens in new window), Click to share on Pocket (Opens in new window), The complicated issue of heavy metals in residential soils, part 2: How plant species and environmental variables complicate the issue, The worms crawl in and the worms crawl out but these worms kill your plants, Hydroponics for the Holidays? Beyond that, I am sure Canadian thistle has plenty of uses and value in ecosystems. Generally these good thistles attract butterflies, sometimes bees, and their seeds are eaten by songbirds. Its root system can be extensive, growing horizontally as much as 18 feet in one season (Nuzzo 1998). Canada thistle can reproduce by seed and has male and female flowers on separate plants. Canada thistle is an aggressively spreading perennial weed that has deep, creeping roots which make it difficult and time-consuming to remove. I felt safe that I was not adding any more of the invasive plant to our environment. In gardens, flower beds, and lawns, Canada thistle’s extensive root system makes it a hassle to control. Enjoy unlimited articles at one of our lowest prices ever. While Canada thistle (not surprisingly) grows throughout much of Canada, this weed also thrives in most of the U.S., as well as Europe and Asia. Get up-to-the-minute news sent straight to your device. Do not pull Canada thistle out, as this can split the root, which causes two Canada thistles to grow back. Combining control methods is the best form of Canada thistle management. Generally, infestations start on disturbed ground, including ditch banks, overgrazed pastures, tilled fields or abandoned sites. Canada Thistle is also a food source for the engrailed moth. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors Obviously the selection process varies widely from state to state. Canada Thistle Where Did it Come From? Symptoms of toxicity can range from weakness to convulsions and should be considered a serious medical condition. It was a look-alike relative -- the innocuous tall thistle -- which is a friend to bumblebees and long-horned bees and butterflies, said Superintendent Brent Meyer. Canada thistle, flowers in South Dakota - Photo by Chris Evans; University of Illinois. Other Montana crops seriously threatened by Canada thistle include peas, corn, beans, alfalfa and sugar beets. Plants primarily regrow and spread from rhizomes, but infestations can also start from seed. 3. Serious problem should equal active efforts to limit the spread. Biennial thistles spread only by seed (achenes) that are produced in great number by all the noxious species, ra… It infests crops, pastures, rangelands, roadsides, and riparian areas (Beck 1996). As mentioned earlier, they thrive in disturbed soils.) In the U.S., it is a host for bean aphid and stalk borer, insects that affect corn and tomatoes (Moore 1975), and for sod-web worm (Crampus sp.) In Canada, the major impact of Cirsium arvense is in agricultural land, and in natural areas that have been disturbed or are undergoing restoration (White et al. Should you ignore the lists? Tall thistles, with silvery leaves, flower in August and September and are a good thistle. The complicated issue of heavy metals in residential soils, part 1: What are toxic heavy metals, and where do they come from? Canada thistle is native to Europe. Ray Eckhart, Master Gardener and loyal blog reader, wrote a long response to Alan’s request for research for the ongoing debate on Canada thistle started a few weeks ago by Jeff. We had a pretty bad outbreak of Canada Thistle (which is a deemed noxious weed in Washington state) a few years ago in our garden. There are the bad thistles -- the musk thistle, the plumeless thistle and the Canada thistle, all with purplish flowers -- which came from other countries without their natural predators to … In Minnesota we do have a process by which weeds are listed — and it as objective a process as I’ve seen for these weeds (it is a bit oligarchical at that!). Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. It was introduced to North America in the 1600s, probably in agricultural seed shipments and is now widespread throughout the United States and Canada. Canada Thistle is not from Canada. Most Canada thistle patches spread at a rate of 3-6 feet/year, crowding out more desirable species and creating thistle monocultures. “Canada thistle threatens productivity in both crop and non-croplands. And although I greatly value your opinion, my skepticism dictates more facts and figures before I’d sign a petition to remove canada thistle from the noxious weed list. It poses an economic threat to the agriculture industry by reducing crop yields.”, Virginia: Canada thistle (Cirsium arvense) is a persistent perennial weed that causes significant crop yield losses. (Of course, the goldfinches would disagree with me!). Extra ten percent yield reduction can occur in alfalfa stands grown for production. Great Courses Chris Evans ; University of Illinois from grazing cumulative and lead a... 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