The wind-dispersed seeds may remain viable for 20 years or more, allowing it to spread quickly and making it difficult to eradicate.”. 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. 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. Once established, it spreads quickly replacing native plants. Canada thistle definition, an Old World plant, Cirsium arvense, having small purple or white flower heads, now a troublesome weed in North America. Livestock do not eat thistles and will not graze between thistle plants on more desirable forage (Batra 1982).”, Invasive.org (linked from .gov sites): 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. Characteristics of Canada thistle are extremely variable when examining populations from different regions. Canada thistle reduces forage consumption in pastures and rangeland because cattle typically will not graze near infestations. Please subscribe to keep reading. The result is a loss of natural diversity. Thickets of thistle crowd out forage grasses in pastures and rangelands, reducing crop yields and productivity. 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 … Please click hereto see a distribution map of Canada thistle in Washington. Brent Meyer, Lancaster County Weed Control Authority superintendent, provided photos of those weeds considered noxious and required to be cont…, Fall is the best time of year to control troublesome weeds in the landscape. Tall thistle flowers in August and September in eastern Nebraska. 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. In cropland, Canada thistle causes extensive yield losses through competition for light, nutrients, and moisture. It also invades wet areas with fluctuating water levels such as stream banks, sedge meadows and wet prairies. Hand-pulling and cultivation are often ineffective control mechanisms because new plants sprout from root pieces that snap off. A stem and a basal clump are shown here, left of the glove. “Canada thistle threatens productivity in both crop and non-croplands. Tall thistles, with silvery leaves, flower in August and September and are a good thistle. Canada thistle. Once it’s here efforts to stop them aren’t usually that effective (sometimes biological controls will work). 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 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. In my opinion Canadian thistle isn’t where it’s at. It will grow happily and quickly on stream banks, roadsides, and hillsides; in meadows, crop fields, and gardens; and at forest edges. At the time I didn't even think to … 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. 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!). Plants primarily regrow and spread from rhizomes, but infestations can also start from seed. 4. 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. But it is more of a bushy plant. Isn’t that the point of these lists to begin with? Infestations of Scotch thistle reduce forage production and virtually prohibit land utilization for livestock It invades natural areas such as prairies and dunes that have disturbance. This time of the year the blooming plant is likely tall thistle, a good thistle, a native thistle. Find the base of the Canada thistle plant and simply snip it off at the base. If the political process is not the way that legal definitions are made, what do you propose as an alternative? 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. Home Systems are a hot holiday gift list item. The standard English name in its native area is creeping thistle. That’s up to you, but if you’re serious about invasive plants then you shouldn’t follow them blindly. Species diversity in an “undisturbed” Colorado grassland was inversely proportional to the relative frequency of Canada thistle (Stachion and Zimdahl 1980). These have been designated as noxious weeds, which landowners are required to control. I think you’ll find that the answer is emerging weed problems rather than weeds which have been here for almost 400 years. 3. Canada Thistle is not from Canada. Similar plants: Stems of Canada thistle are not spiny in contrast to bull thistle (Cirsium vulgare) and nodding thistle (Carduus nutans). If treated properly and in a timely manner using medication and intravenous … 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. Jimsonweed and poison ivy are native and on many state lists. Musk thistles flower in May and June and don't have any silver on their leaves. 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. Sorry, Jeff. In pastures, Canada thistle reduces productivity by crowding out forage species with spiny leaves that deter cattle from grazing. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors I make a distinction between noxious and invasive, first off. Seed production is usually completed in early July. “Impacts Agricultural: Canada thistle is an aggressive, creeping, perennial weed. Its root system can be extensive, growing horizontally as much as 18 feet in one season (Nuzzo 1998). 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. It has its community niches to fill, its services to the system to do. Infestations reduce crop yield through competition for water, nutrients and minerals (Malicki and Berbeciowa 1986) and interfere with harvest (Boldt 1981). ), From the Minnesota pdf referenced above: Why is Canada thistle so tenacious? 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. Canada thistle, flowers in South Dakota - Photo by Chris Evans; University of Illinois. 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. Canada Thistle Where Did it Come From? There are more, but I stopped on page 3 of the 120 page result of the google .edu search. It is known to harbor other pest species, e.g., insects, and has long been recognized as an agricultural est. Spreading both by seed and rhizome, Canada thistle can create monocultures covering large areas. “Some noxious or invasive weeds are highly toxic to equines, however, and can cause tremendous problems if allowed to invade horse pastures. Canada thistle (Cirsium arvense) is a persistent perennial weed that causes significant crop yield losses. A single Canada thistle plant can release more than 5,000 plumed seeds, easily carried several yards by the wind. An Oligarchcal Committee of Horticulturists unswayed and uswayable by political interests? Canada thistle — which is actually not native to North America — is a perennial, so it is harder to control. Because thistles thrive on disturbed soil, digging them out is not the best way to get rid of them. But it wasn’t musk thistle growing near the creek. “Noxious weeds are difficult to control and injurious to public health, the environment, roads, crops, livestock and property. In gardens, flower beds, and lawns, Canada thistle’s extensive root system makes it a hassle to control. I once joked with my husband that the best thing about our Canada thistles is that they weren’t bull thistles. See more. Enjoy unlimited articles at one of our lowest prices ever. Where you find tall thistle you usually find bees and butterflies and birds, Meyer said. 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. 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. Others will disagree. It actually came from Europe. 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. I felt safe that I was not adding any more of the invasive plant to our environment. 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 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. This may be partially due to the extensive taproot in many broadleaf weeds that allow them to remain green longer into the dry season, thereby appearing potentially attractive to horses grazing in poor pastures. 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. Cirsium arvense presents an economic threat to farmers and ranchers. 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. 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? Get up-to-the-minute news sent straight to your device. aggressive root spread crowds out It also invades wet areas with fluctuating water levels such as streambanks, sedge meadows, and wet prairies. 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. 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!) Musk thistle flowers in May and June in the eastern part of the state. Enter your email address to subscribe to this blog and receive notifications of new posts by email. (Of course, the goldfinches would disagree with me!). Nancy Hicks reports on Lincoln city government, but she’s been following the leaders of local and state government for more than 40 years. Add livestock and dairy interests, and I think you’re tilting at windmills with your fellows on the committee. 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. then {{format_dollars}}{{start_price}}{{format_cents}} per month. 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. A combination of mowing and herbicides is best, Eckberg said. “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: It also increases harvesting problems due to seed and forage contamination. 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. It releases chemicals toxic to other plants. Generally, infestations start on disturbed ground, including ditch banks, overgrazed pastures, tilled fields or abandoned sites. 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. Kentucky: Canada thistle invades natural areas such as prairies, savannas, open areas in forests, and dunes if some degree of disturbance already exists. “Thistles are pioneer species and are most often found in sites where the ground cover has been disturbed by grazing, erosion, traffic, or other means. It is also commonly known as Canada thistle and field thistle.. It produces nitrate, which can be toxic to your horse if ingested in large quantities. In fact, improper cultivation can even worsen Canada thistle problems!”, From Pennsylvania: 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. These seeds … 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. “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.) Canada thistle is a cool season perennial which spreads by seed and vegetatively by creeping roots. Wildflowers Of WisconsinWild… “Why is it a noxious weed? They are not on our list but I’ve had enough pain from them to consider them Devil’s spawn! It reproduces through both seed and root regeneration, but the latter is the most successful. These prickles are an adaptation that protects the plant from being eaten by herbivores. When I started feeding thistle to the birds, I heard somewhere that it will not germinate. Only recently have the harmful impacts of Canada thistle to native species and natural ecosystems received notable attention.”, Idaho: “Canada thistle threatens productivity in both crop and non-croplands. Canada thistle is a perennial that spreads by seed and an underground system of vertical and horizontal roots. Symptoms of toxicity can range from weakness to convulsions and should be considered a serious medical condition. Canada thistle (Cirsium arvense) is a perennial that has plagued farmers in America since European settlement, and is a Noxious Weed in Pennsylvania. 2nd Cite for Pennsylvania: Canada thistle is a creeping perennial that reproduces from vegetative buds in its root system and from seed. 1993). 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. because of their invasive nature.”. Garlic mustard has been here since colonial times and is on many lists, and makes a fine pesto. Heavy infestations are also commonly found in overgrazed pastures and ranges and may crowd-out and replace native grasses and forbs, decreasing species diversity in an area. 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.”. The aesthetic value of a pasture is also impacted by weeds. In Bulgaria Cirsium arvense is a host for the cucumber mosaic virus (Dikova 1989). “Human: Spiny thickets of Canada thistle can restrict recreational access to infested areas.”, South Dakota: So Meyer is hoping a little education will help people distinguish between good and bad thistles with pinkish-purple flowers. Livestock owners hate it and see it only as an invasive plant, especially since few domestic animals will feed on it. You emphasize the economic costs of control, while downplaying the economic costs of non-control to the Ag industry. An extra ten percent yield reduction can occur in alfalfa seed production due to seed cleaning. Email notifications are only sent once a day, and only if there are new matching items. Most Canada thistle patches spread at a rate of 3-6 feet/year, crowding out more desirable species and creating thistle monocultures. 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. Advancing the science of gardening and other stuff since 2009. In some cases it may lead to cuts and sometimes infections — but it’s not toxic. As mentioned earlier, they thrive in disturbed soils.) In non-cropland ecosystems, Canada thistle can crowd out and replace native grasses and forbs limiting land’s recreational use. Prickles can also occur all over the plant – on the stem and on the flat parts of the leaves. All biennial thistles considered noxious are native to Europe or Eurasia, and were introduced into North America as seed contaminants. “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. Tall thistle is often found in drainage ditches and wetland areas and not in pastures. The thistle gained a bad reputation when people interacted with its prickles and when it made its way onto their properties. Beyond that, I am sure Canadian thistle has plenty of uses and value in ecosystems. 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? “Weeds can reduce the quantity and the stand life of desirable forage plants in pastures and hayfields. Most native thistles are either silver or light greenish-gray in color, or have some silver on parts of the plant, he says. Because he has a lot of links to research in his response, I thought it should have its own posting. It is difficult to control because its extensive root system allows it to recover from control attempts. Canada thistle is native to Europe. Canada thistle is an aggressively spreading perennial weed that has deep, creeping roots which make it difficult and time-consuming to remove. Additionally, plants can spread by growing in circular … From Montana: The … Ask yourself what weeds you can target where it will make the most difference. In addition to reducing forage and pasture production, Canada thistle may scratch grazing animals, resulting in small infections (Moore 1975).”, Washington State: Thistles reduce the use of an area for grazing or recreational purposes because of the prominent spines on leaves, stalks, and blooms. 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. It is also known as cursed thistle, probably due to the fact that chopping the roots with a plow effectively spreads the thistle across a field. A Monarch butterfly feeds on a native tall thistle. Most of the seeds germinate within a year, but some may remain viable in the soil for up to … 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. I'm sure its tap root is quite good for loosening and building soil. Hydroponics for the Holidays? Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). “Threats: Canada thistle’s rapid growth aggressively competes with native plants and crops for nutrients, moisture and light. Combining control methods is the best form of Canada thistle management. You have permission to edit this article. When thistle starts sprouting in their yards, some determine to never use this feed again. The horse people I have only a nodding acquaintance with, are the Point-to-Point Steeplechase folks of the DC exurbs in Virginia. That said, Canadian thistle is listed because of political pressure (I do sit on the Minnesota Department of Agriculture’s committee which reviews these weeds). Canada thistle is common in pastures and croplands. Canada Thistle is also a food source for the engrailed moth. {{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. Serious problem should equal active efforts to limit the spread. Do not pull Canada thistle out, as this can split the root, which causes two Canada thistles to grow back. Other Montana crops seriously threatened by Canada thistle include peas, corn, beans, alfalfa and sugar beets. “Ecological: Canada thistle spreads rapidly through horizontal roots, which give rise to shoots (Moore 1975). 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. But why is it so tough to get rid of Canada thistle and what is the best way to do so? 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. 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. 1. 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. They are a noxious weed. We (the people of this country) only have so much in the way of resources to combat invasive plants and noxious weeds, so we need to do our best to focus our efforts where it really matters. Canada thistle can reproduce by seed and has male and female flowers on separate plants. which damages corn (Detmers 1927). One reference points out that Canadian thistle is toxic to horses — that’s wrong. native to Europe and Asia introduced to Canada as a contaminant of a crop seed in the early 1600s has spread throughout most of the continental United States and Alaska Why is it Bad? We need a comparison to rate the relative harm of CT.