Don’t allow spray to come in contact with any desirable vegetation. (Musk Summer. Musk thistle is continuous throughout the United States. Gilpin County Extension is your information source. Homeowners can use glyphosate or 2,4-D herbicides, when temperatures are 60 to 85 degrees Fahrenheit, and when winds are less than five miles per hour. Share on Twitter. The leaves are dark green, coarsely bipinnately lobed, with a smooth, waxy surface and sharp yellow-brown to whitish spines at the tips of the lobes. As with any pesticide, read herbicide label directions carefully and follow them explicitly. Meadows, Species not present in state, Species present and not rare Carduus nutans Flowers. Meadows, It reproduces by seed which it During the second year, the stem bolts and can grow 2 to 6 feet tall. PINK/RED/ORANGE Colorado State University Extension can provide relief by offering reliable research-based information. US, NOXIOUS Navajo Lake Trail, August 30, 2007. Contact your local county Extension office through our County Office List. Plants may resprout. Forward by Email. Through our 4-H programs, we help youth develop life skills and to become more interested in Science, Technology, Engineering and Math (STEM) learning. The product 2, 4-D can be applied in the early spring before the head shoot begins to grow. The leaves are very prickly-spiny, and often have a white margin. Leaves are 3 to 6 inches long and are dark green in color with a prominent midrib. Range map © John Kartesz, Rosettes can appear in either spring or fall. The key to successful musk thistle control is to prevent seed production. Click here to view the history of PlantTalk Colorado. Continual mowing or chopping is most effective when musk and Scotch thistle plants are just beginning to flower. Mowing can effectively reduce seed output if plants are cut when the terminal head is in the late-flowering stage. Musk thistle is a biennial, which means it lives only two years. CSU A-Z Search Musk thistle or nodding thistle (Carduus nuttans) is a biennial forb in the Aster family. Semi-desert, foothills, montane, subalpine. Above: Grows in all soil textures, but soils must be well drained Floristic Synthesis of North America A thick taproot produces a large, spreading, basal rosette of sharply armed leaves. Seeds germinate even under relatively dry conditions. Overgrazed sites result in bare spots which are prime targets for noxious weed infestations. Disclaimer | Apply herbicides such as Tordon, Milestone, Transline, Perspective, Vanquish/Clarity or 2,4-D to musk thistle rosettes in spring or fall. Species noxious 4. As the photographs at the top of the page show, Carduus nutans can grow to enormous heights. Most effective control methods. The key to musk thistle control is to halt seed production. Severing the tap root below the soil surface with a shovel can also effectively kill the plant. It’s a noxious weed prevalent in open spaces, vacant lots, pastures, ditch banks and along roadsides. Herbicides that are recommended for use on musk and Scotch thistle, either independently or in combination, are: picloram(Tordon 22K), clopyralid(Transline, Stinger), clopyralid plus 2,4-D(Curtail), chlorsulfuron(Telar), glyphosate(Roundup/Rodeo), dicamba(Banvel), and 2,4-D. At this stage, the plant may grow two to six feet tall. Herbicides are most effective when used on first year rosettes, especially in late summer or fall. Musk thistle will not tolerate tillage and can be removed easily by severing its root below ground with a shovel or hoe. In the plant’s second growing season, it sends up multiple flowering stems. With the millions of websites on the internet, it's hard to know who to trust for information. 700 Jefferson County Parkway, Suite 100 Golden CO 80401, Coronavirus/COVID-19 Updates and Resources, Rosettes formed the first year and bolt early in May to June of the next year, Grows in all soil textures, but soils must be well drained, Musk thistle out-competes desirable plants for resources, Pastures, rangeland, forests, disturbed areas, right-of-ways, ditch banks and grain fields from sea level to 8,000 feet, Leaves are hairless, dark green with light green mid-rib, deeply lobed; 1  to 1 1/2 inches wide and 4 to 5 inches long; yellow to white spine near tip, Leaves extend onto the stem, giving it a winged appearance, Buds 1 inch or less wide; mature flowers are 1 1/2 to 3 inches wide, Droop from stem, giving it the name "nodding thistle", Each head produces an average of 1,200 to 1,500 seeds 45 to 55 days after bolting, Seed is dispersed 7 to 10 days after flowering, Can germinate 6 to 8 weeks after falling to ground, May remain dormant in soil for more than 10 years, Rosettes can grow up to 4 feet in diameter, Removal – hand pulling before seed set; remove at least the top 2 to 4 inches of the root, Burning - Fire has not been and effective control because it doesn’t get hot enough to kill the plant and its roots. rosettes just below ground level. Disclaimer | roadsides, and disturbed mountain fields. Carduus nutans is a non-native species that can be a serious threat to native plants  --  but Carduus nutans flowers sure are gorgeous and thoroughly enjoyed by a number of insects. Once established it spreads rapidly because of the large number of seeds produced. CSU A-Z Search Biennial plant which reproduces only by seed; to successfully manage musk thistle, prevent seed formation. Species present in state and exotic This should be done in areas where there are only a few plants though as this option is quite labor intensive and time consuming. It invades many types of habitats but is a serious threat to pastures as it is unpalatable to livestock. Musk Thistle Musk thistle is a biennial which means it only lives for two years. In the first year, it germinates from seed and grows into a low-growing rosette of leaves. Because musk thistle reproduces solely from seed, the key for successful management is to prevent seed production. Seeds may remain dormant in soil for over 10 years. In the first year, it germinates from seed and grows into a low-growing rosette of leaves. The plant then dies; it is a biennial. The plants develop a rosette, with large leaves 30–60 centimetres (12–24 in) long. Privacy Statement | A research project was initiated in 2014 on a 10,670-acre ranch near Cimmarron, Colorado (Figure 1) to develop sustainable management strategies for musk and Canada thistle. Carduus nutans is a prickly, menacing and beautiful, common, foreign invader of lawns, farm fields, roadsides, and disturbed mountain fields. Musk thistle has sharply spiny stems and leaves. Mowing can effectively reduce seed output if plants are cut when the terminal head is in the late-flowering stage. Gather and burn mowed debris to … General. When used together, the crown and seedhead weevils provide fair to good control. Nominations are being sought to fill three positions within the Noxious Weed Advisory Committee. It invades many types of habitats but is a serious threat to pastures as it is unpalatable to livestock. Carduus nutans (Musk Thistle, Nodding Thistle) Asteraceae (Sunflower Family) Semi-desert, foothills, montane, subalpine. Mowing can effectively reduce seed output if plants are cut when the terminal head is in the late-flowering stage. Mowing musk thistle in its second year is effective if it’s done before any flowers mature. Meadows, It is a biennial weed, although occasionally it is an annual. Prevention of this plant's invasion is the best form of management. Mesa Verde National Musk thistle is usually found as a single plant rather than in dense colonies like Canada thistle and leafy spurge. City of Longmont, Colorado: Musk Thistle Field Day. 2. Employment | They are more or less hairy on top, and wooly on the veins below. No specific recommendation or endorsement is made or implied by listing methods or products. Gather and burn mowed debris to destroy any seed that has developed. to nodding flowers, which are seldomly seen in the Four Corners region. For musk thistle, herbicides can be used prior to the time buds begin to show a little pink. Keep it simple.) In the top photograph Betty has 9 foot Carduus nutans towering over her. CONTACT This insect alone does not affect total control of musk thistle infestations. Print. Eradicated Privacy Statement | To rid your property of this invasive species, do a thistle patrol several times during the summer and fall and use a shovel to cut the The CSU Extension in Gilpin County helps mountain residents improve their quality of life by offering a website, classes and programs that provide unbiased, research-based information on forestry, wildfire, wildlife, mountain gardening, noxious weeds and many other issues. In the second year, this basal rosette will sprout a thick stem which will branch and produce many flowers, each of which will produce a prodigious number of seeds.