This time of year musk thistle is usually dried up and has fallen over, Meyer said. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). When thistle starts sprouting in their yards, some determine to never use this feed again. Canada thistle reduces forage consumption in pastures and rangeland because cattle typically will not graze near infestations. “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. Should you ignore the lists? Only recently have the harmful impacts of Canada thistle to native species and natural ecosystems received notable attention.”, Idaho: Canada thistle (Cirsium arvense) is a persistent perennial weed that causes significant crop yield losses. In addition to reducing forage and pasture production, Canada thistle may scratch grazing animals, resulting in small infections (Moore 1975).”, Washington State: 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. These seeds … Its root system can be extensive, growing horizontally as much as 18 feet in one season (Nuzzo 1998). 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. Most people see it as an aggressive weed, and they have no idea it has many useful treats for homesteaders and preppers alike. “THREATS POSED BY THIS SPECIES: Natural areas invaded by Cirsium arvense include prairies and other grasslands in the midwest and Great Plains and riparian areas in the intermountain west. Seed production is usually completed in early July. It helps heal land by keeping people and livestock off it, for one thing! Bull thistles (Cirsium vulgare) are exactly that – bullish. You emphasize the economic costs of control, while downplaying the economic costs of non-control to the Ag industry. Canada thistle is diecious, which means male and female flowers occur on separate plants. It is also commonly known as Canada thistle and field thistle.. 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. because of their invasive nature.”. Troublesome statewide noxious weeds like Canada thistle, leafy spurge, perennial sow thistle, Russian knapweed, and hoary cress can be serious problems in pasture and rangeland.”. From Montana: 2nd Cite for Pennsylvania: By law, these weeds must be controlled on all public and private lands.”. “Human: Spiny thickets of Canada thistle can restrict recreational access to infested areas.”, South Dakota: Characteristics of Canada thistle are extremely variable when examining populations from different regions. In some cases it may lead to cuts and sometimes infections — but it’s not toxic. Canada thistle. Nope, I’m still on the cavalier side — at least as Canadian thistle compares to other weeds. If treated properly and in a timely manner using medication and intravenous … Cirsium arvense presents an economic threat to farmers and ranchers. Biology. then {{format_dollars}}{{start_price}}{{format_cents}} per month. Note the running roots, which can persist and keep sprouting even through a year or two of frequent pulling or spraying with herbicide. The reference from Montana points out that two thistles per square yard can have a significant effect on the growth of crops — I certainly believe that, but then many other weeds will do the same thing so I don’t see why that information should make this weed significantly worse than others. Flowers are pink, bristly, 1/2 inch long and wide. View all posts by Linda Chalker-Scott. In cropland, Canada thistle causes extensive yield losses through competition for light, nutrients, and moisture. Controlling Canada thistle organically is done with a sharp eye and an even sharper pair of scissors. In Montana, it is estimated that two shoots per square yard can reduce wheat yield by 15 percent and 25 shoots per square yard can reduce wheat yield by 60 percent. Canada thistle (Cirsium arvense) is a perennial that has plagued farmers in America since European settlement, and is a Noxious Weed in Pennsylvania. In 2002, the Colorado Department of Agriculture surveyed counties and while incomplete, the results showed more than 100,000 acres infested with Canada thistle (Figure 1).”. A stem and a basal clump are shown here, left of the glove. Cirsium arvense is a perennial species of flowering plant in the family Asteraceae, native throughout Europe and western Asia, northern Africa and widely introduced elsewhere. Some callers are insistent that this is musk thistle, the evil plant that chokes out all other plants, covers pastures and range land with inedible spiny plants. If the political process is not the way that legal definitions are made, what do you propose as an alternative? (* about $6500 of my annual salary and benefits comes from fulfilling Master Gardener responsibilities. I have to agree with Jeff’s first comment. Once it’s here efforts to stop them aren’t usually that effective (sometimes biological controls will work). It will grow happily and quickly on stream banks, roadsides, and hillsides; in meadows, crop fields, and gardens; and at forest edges. “Threats: Canada thistle’s rapid growth aggressively competes with native plants and crops for nutrients, moisture and light. Canada thistle invades natural communities primarily through vegetative expansion, and secondarily through seedling establishment. 1. It’s commonly accepted that the time to stop a weed is when it first appears. So Meyer is hoping a little education will help people distinguish between good and bad thistles with pinkish-purple flowers. Bob Rodgers at Survivopedia has an article on Why You Need to Use Thistle for Food and Medicine. Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In pastures, Canada thistle reduces productivity by crowding out forage species with spiny leaves that deter cattle from grazing. She is WSU’s Extension Urban Horticulturist and an Associate Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. which damages corn (Detmers 1927). Canada thistle produces an abundance of bristly-plumed seeds which are easily dispersed by the wind. There was a problem saving your notification. An extra ten percent yield reduction can occur in alfalfa seed production due to seed cleaning. They are not on our list but I’ve had enough pain from them to consider them Devil’s spawn! Canada thistle, flowers in South Dakota - Photo by Chris Evans; University of Illinois. Stay up-to-date on the latest in local and national government and political topics with our newsletter. I’ll leave it to others more qualified than I am to further debate the relative merits of why or why not a more cavalier (heh!) Basically the citations above point out that this stuff is a weed — which we already knew — I just don’t see this information raising Canadian thistle to the level of noxious weed. It releases chemicals toxic to other plants. It invades natural areas such as prairies and dunes that have disturbance. Most native thistles are either silver or light greenish-gray in color, or have some silver on parts of the plant, he says. ), From the Minnesota pdf referenced above: 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. Canada thistle or Canadian thistle, featured here, is native to Eurasia, where it is known as creeping thistle, due to its ability to spread via roots into dense patches. It stores food energy in its extensive root system both to survive the winter and to fuel the plant's reproductive drive the following season. Even research can be suspect if, as Jeff points out, the thistle isn’t being compared with other weeds as opposed to pristine growing conditions. Weeds can also diminish the quality and palatability of the forage available for livestock grazing, and certain weed species are potentially poisonous to grazing animals. Other Montana crops seriously threatened by Canada thistle include peas, corn, beans, alfalfa and sugar beets. How can one differentiate between fact and baseless opinion when no actual research is presented as is the case with the danger stated of thistle to pasture. Of the 11 on the Minnesota list, can you rank them, and tell us why or why not they should be on there? A single Canada thistle plant can release more than 5,000 plumed seeds, easily carried several yards by the wind. At the time I didn't even think to … How Did it Get Here? One reference points out that Canadian thistle is toxic to horses — that’s wrong. Can we ignore these lists, based on what you say here? It grows in circular patches, spreading vegetatively through roots which can spread 10 -12′ in one season. While Canada thistle is the main problem species in this section, there are several other weeds we aim to eliminate such as bindweed, creeping purslane, and pigweed, which have been treated and will be observed as well. Books: http://www.sustainablelandscapesandgardens.com Hydroponics for the Holidays? 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. It poses an economic threat to the agriculture industry by reducing crop yields.”, Virginia: Get up-to-the-minute news sent straight to your device. Combining control methods is the best form of Canada thistle management. As mentioned earlier, they thrive in disturbed soils.) “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. The horse people I have only a nodding acquaintance with, are the Point-to-Point Steeplechase folks of the DC exurbs in Virginia. As it establishes itself in an area, Canada thistle crowds out and replaces native plants, changes the structure and species composition of natural plant communities and reduces plant and animal diversity. Tall thistle is often found in drainage ditches and wetland areas and not in pastures. About half the calls to Meyer’s office this month are from people reporting stands of musk thistle, a noxious weed. Purple loosestrife has been established for over 200 years, and is quite beautiful, with medicinal properties. We need a comparison to rate the relative harm of CT. 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. Species diversity in an “undisturbed” Colorado grassland was inversely proportional to the relative frequency of Canada thistle (Stachion and Zimdahl 1980). “Edibility” thus becomes a non-factor, since it ignores the obvious “You can led a horse to thistle, but you can’t make him eat” factor, and the converse of a fine forage food (and erosion control conservation benefits) in the case of kudzu doesn’t change its undesirability. Canada thistle is a native plant to regions of Europe and Asia but is considered noxious everywhere else. Michael Bociurkiw writes that as the US has struggled to flatten the curve on the coronavirus pandemic, its neighbor to the north -- Canada -- has successfully managed to slow the spread of Covid-19. As an analogy, You can call yourself a race car driver, but that doesn’t make you one, and I wouldn’t believe you are one without some kind of proof — like an article showing how well you’d done in a race last week. Wildflowers Of WisconsinWild… Canada thistle can reproduce by seed and has male and female flowers on separate plants. And then there are the good thistles, native to Nebraska -- the tall thistle, Flodman thistle, wavyleaf thistle and Platte thistle -- which may get a little frisky for a season or two but are put in their rightful, limited place by natural Nebraska predators. 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? Infestations reduce crop yield through competition for water, nutrients and minerals (Malicki and Berbeciowa 1986) and interfere with harvest (Boldt 1981). They were quiet, pretty, often-mowed places that gave us green and shade in the urban env…. Obviously the selection process varies widely from state to state. Native To: Europe . Ask yourself what weeds you can target where it will make the most difference. 3. Kentucky: These prickles are an adaptation that protects the plant from being eaten by herbivores. Spreading both by seed and rhizome, Canada thistle can create monocultures covering large 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. Isn’t that the point of these lists to begin with? An Oligarchcal Committee of Horticulturists unswayed and uswayable by political interests? It also invades wet areas with fluctuating water levels such as streambanks, sedge meadows, and wet prairies. On what basis should folks like you be more or less cavalier? It also increases harvesting problems due to seed and forage contamination. This highly invasive thistle prevents the coexistence of other plant species through shading, competition for soil resources and possibly through the release of chemical toxins poisonous to other plants. “Noxious weeds are found in range and pasture as well as noncrop areas and cropland. The wind-dispersed seeds may remain viable for 20 years or more, allowing it to spread quickly and making it difficult to eradicate.”. Find the base of the Canada thistle plant and simply snip it off at the base. Both natural and human caused disturbances can create the opportunity for Canada thistle to become established in natural communities.”, Ohio: Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. In gardens, flower beds, and lawns, Canada thistle’s extensive root system makes it a hassle to control. There are more, but I stopped on page 3 of the 120 page result of the google .edu search. I think you’ll find that the answer is emerging weed problems rather than weeds which have been here for almost 400 years. The plant is beneficial for pollinators that rely on nectar. It actually came from Europe. 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!). If you’re in an area where Canada thistle creates a serious problem in pastures or other areas, then it’s of more concern than in areas where it’s a minor nuisance. "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors 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? 4. Canada Thistle is also a food source for the engrailed moth. “In the Northeast, several weeds including bull and musk thistle, Canada thistle, purple loosestrife (Lythrum salicaria), mile-a-minute (Polygonum perfoliatum), and garlic mustard (Allaria petifolia) are receiving attention [for biological control efforts – ed.] In cropland, Canada thistle causes extensive yield losses through competition for light, nutrients, and moisture. Sorry, Jeff. Canada thistle is a creeping perennial that reproduces from vegetative buds in its root system and from seed. It infests crops, pastures, rangelands, roadsides, and riparian areas (Beck 1996). Not Your Average Thistle The key to Canada thistle's weediness is its root system. It has its community niches to fill, its services to the system to do. This is an interesting discussion but I’m very confused. Advancing the science of gardening and other stuff since 2009. 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. “Canada thistle threatens productivity in both crop and non-croplands. Organic Canada Thistle Control. Canada thistle is native to Europe. “In alfalfa stands grown for seed production, Canada thistle can reduce yield by 48 percent. 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 non-cropland ecosystems, Canada thistle can crowd out and replace native grasses and forbs limiting land’s recreational use. But it wasn’t musk thistle growing near the creek. Beyond that, I am sure Canadian thistle has plenty of uses and value in ecosystems. Because thistles thrive on disturbed soil, digging them out is not the best way to get rid of them. Please subscribe to keep reading. You can cancel at any time. See more. ECOLOGICAL THREAT: Natural communities that are threatened by Canada thistle include non-forested plant communities such as prairies, barrens, savannas, glades, sand dunes, fields and meadows that have been impacted by disturbance. Plants primarily regrow and spread from rhizomes, but infestations can also start from seed. Home Systems are a hot holiday gift list item – GRO Big Red, The complicated issue of heavy metals in residential soils, part 2: How plant species and environmental variables complicate the issue – The Garden Professors™. Canada Thistle Where Did it Come From? Serious problem should equal active efforts to limit the spread. Canada thistle is an aggressively spreading perennial weed that has deep, creeping roots which make it difficult and time-consuming to remove. The points from Invasive.org are well made, particularly because they cite research that shows exactly what Canadian thistle is capable of — but in my opinion they over interpret the results. But it is more of a bushy plant. In cases of the varieties mentioned above, intoxication can be cumulative and lead to a variety of clinical signs. Scientific Name: Cirsium arvense (L.) Scop (ITIS) Common Name: Canada thistle, Californian thistle, Canadian thistle, creeping thistle, field thistle, corn thistle, perennial thistle, field thistle. Tall thistles, with silvery leaves, flower in August and September and are a good thistle. Tall thistle has silver color on the underside of its leaves. Because he has a lot of links to research in his response, I thought it should have its own posting. They are a noxious weed. “Canada thistle is declared a “noxious weed” throughout the U.S. and has long been recognized as a major agricultural pest, costing tens of millions of dollars in direct crop losses annually and additional millions costs for control. The … This isn’t intended to be a defense of Canadian thistle- only a statement of a desire for a more scientific evaluation. “Weeds can reduce the quantity and the stand life of desirable forage plants in pastures and hayfields. “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: “Impacts Agricultural: Canada thistle is an aggressive, creeping, perennial weed. approach other than current government regulatory action is or is not warranted. 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 … Field bindweed has also been around since colonial times. (Of course, the goldfinches would disagree with me!). Because of its contribution to the persistence of the weed, Canada thistle's extensive root system must be the target of an effective control program. Canada thistle definition, an Old World plant, Cirsium arvense, having small purple or white flower heads, now a troublesome weed in North America. 1993). 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. “Why is it a noxious weed? Biennial thistles, such as musk (Carduus nutans L.), plumeless (Carduus acanthoides L.) and bull thistle [Cirsium vulgare (Savi) Tenore], are not as difficult to control as the perennial thistle species, but spread rapidly and can become severe problems in some areas. Were I in your position, I’d spend my “Political Capital”, on eliminating all the native, beneficial species on the Minnesota secondary noxious weed list bannable at the county level by petition. Tall thistle is generally no taller than musk thistle -- 5 to 7 feet tall. All biennial thistles considered noxious are native to Europe or Eurasia, and were introduced into North America as seed contaminants. Canada thistle (Cirsium arvense) is a root-creeping perennial. Still not convinced. Thickets of thistle crowd out forage grasses in pastures and rangelands, reducing crop yields and productivity. The standard English name in its native area is creeping thistle. The problem is … “Some noxious or invasive weeds are highly toxic to equines, however, and can cause tremendous problems if allowed to invade horse pastures. Virginia is a prime example in that there are only two weeds listed yet neighboring North Carolina, with very similar climate and growing conditions, lists over a hundred. Grazing animals will not eat anywhere near where Canada Thistle grows, so if you own horses or cows, a bad infestation of Canada Thistle in your pastures can cause problems. The complicated issue of heavy metals in residential soils, part 1: What are toxic heavy metals, and where do they come from? This time of the year the blooming plant is likely tall thistle, a good thistle, a native thistle. 2nd cite Colorado: The result is a loss of natural diversity. It also increases harvesting problems due to seed and forage contamination. The thistle gained a bad reputation when people interacted with its prickles and when it made its way onto their properties. Canada thistle invades natural areas such as prairies, savannas, open areas in forests, and dunes if some degree of disturbance already exists. In Indiana, Canada thistle normally initiates growth in spring, reaches the flower-bud stage the first week in June, and full flower about the third week of June. The aesthetic value of a pasture is also impacted by weeds. Similar plants: Stems of Canada thistle are not spiny in contrast to bull thistle (Cirsium vulgare) and nodding thistle (Carduus nutans). It is known to harbor other pest species, e.g., insects, and has long been recognized as an agricultural est. And the difference can be confusing, particularly when they look so much alike. Enjoy unlimited articles at one of our lowest prices ever. These have been designated as noxious weeds, which landowners are required to control. So, to go to Ray’s question about a cavalier attitude, my opinion is it varies just as widely as the state decision making process. Personally, I say destroy every one of the nasty things you see. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors Deer tend to avoid it, though. Where you find tall thistle you usually find bees and butterflies and birds, Meyer said. Musk thistles flower in May and June and don't have any silver on their leaves. {{start_at_rate}} {{format_dollars}} {{start_price}} {{format_cents}} {{term}}, {{promotional_format_dollars}}{{promotional_price}}{{promotional_format_cents}} {{term}}, Outgoing AG Barr: 'No reason' for special counsel on election fraud, Biden's son, How to tell the evil weeds from the merely annoying, Sarah Browning: Fall is best time to control tough weeds, Sarah Browning: Choosing a good tree and getting it started, Here's how Lincoln plans to add beauty and butterflies to city parks, WATCH: City news conference on coronavirus restrictions in Lincoln, Mayor Beutler gives parting thoughts to Lincoln community, Council candidate Stock recalls memorable campaign moment, Council candidate Meginnis recalls memorable campaign moment. aggressive root spread crowds out She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. I once joked with my husband that the best thing about our Canada thistles is that they weren’t bull thistles. Infestations of Scotch thistle reduce forage production and virtually prohibit land utilization for livestock It produces nitrate, which can be toxic to your horse if ingested in large quantities. These unwanted plants are often more aggressive than existing or desired forage species and compete for light, water, and nutrients. Occur in alfalfa stands grown for seed production, Canada thistle in Washington current regulatory... And wet prairies typically will not graze near infestations a rate of 3-6 feet/year, out... Arvense, which can be cumulative and lead to cuts and sometimes infections — but it ’! As noxious weeds, which means male and female flowers occur on separate plants crop and! Then you shouldn ’ t usually that effective ( sometimes biological controls will work.... Once a day, and lawns, Canada thistle include peas, corn, beans, alfalfa and sugar.! Crops seriously threatened by Canada thistle and what is the objective, neutral, criteria that qualifies weed. Horses — that ’ s up to you, but infestations can also start from seed them... Update of Art Kruckeberg’s Gardening with native plants than current government regulatory action is or is not best. Starts sprouting in their yards, some determine to never use this feed again in their,... Uses and value in ecosystems way to do and hayfields thing about our Canada thistles to back... Subscribe to this blog and receive notifications of new posts by email by keeping people and livestock off,! Cirsium vulgare ) are exactly that – bullish the standard English name in its native is! Source for the cucumber mosaic virus ( Dikova 1989 ) areas with fluctuating levels. Years, and moisture in may and June and do n't have any silver on parts the! 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Invasive plant, he says, overgrazed pastures, Canada thistle ’ s wrong to limit spread! I heard somewhere that it will not germinate beautiful, with silvery leaves, flower in and. Said Meyer we ignore these lists, based on what you say here our... Effort is an ISA certified arborist and an ASCA consulting arborist, creeping perennial... S up to you, but infestations can also start from seed and! And invasive, first off Nuzzo 1998 ) of WisconsinWild… Canada thistle is abundant, said Meyer,. Gardening with native plants meadows, and makes a fine pesto loosestrife has been here since colonial times the thistle..., Meyer said spreads by seed and rhizome, Canada thistle is a season! Have disturbance and makes a fine pesto plant, especially since few animals. Of thistle crowd out and replace native why is canada thistle bad and forbs limiting land ’ s spawn root regeneration but. Was not adding any more of the Canada thistle, a good thistle plant on! All public and private lands. ” of academic colleagues who educate and entertain through their and... When they look so much alike so what is the best thing about our Canada thistles is that they ’... Land by keeping people and livestock off it, for one thing calls to ’! Non-Control to the Ag industry they are not on our list but I ’ ve had enough from... Yards, some determine to never use this feed again plant can release more than a hundred noxious and... The wind and soil sciences, publishing the results in scientific articles and University Extension fact sheets downplaying. Articles at one of our lowest prices ever year, perhaps because of a pasture is impacted. Cropland, Canada thistle spreads rapidly through horizontal roots regions of Europe and but! Year the blooming plant is beneficial for pollinators that rely on nectar than existing or desired species..., creeping, perennial weed that has deep, creeping roots for 200! Thistles with pinkish-purple flowers or recreational purposes because of the 120 page result of the 120 page result of Garden. A comparison to rate the relative harm of CT holiday gift list item, sometimes,! T follow them blindly and replace native grasses and forbs limiting land ’ s first comment make it to! The flat parts of the DC exurbs in Virginia he has a Ph.D. in Horticulture from Oregon University! Crop and non-croplands with our newsletter will help people distinguish between good and bad thistles with flowers... Buds on the latest in local and national government and political topics with our.! Than weeds which have been here for almost 400 years in their yards some! Pair of scissors, spreading vegetatively through roots which make it difficult time-consuming. It ’ s here efforts to limit the spread in August and September in eastern Nebraska seeds, easily why is canada thistle bad... 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Please click hereto see a distribution map of Canada thistle reduces productivity by crowding out more desirable why is canada thistle bad and thistle...