Public and private landowners are not required to control infestations of bull thistle that occur on their property in King County. Additionally, native thistles are noticeably less prickly than weedy, non-native thistles, like bull thistle (Cirsium vulgare) or Canada thistle (Cirsium arvense). The second true leaf is dark green and covered densely with white hairs on the upper surface. Note: Chemical control should only be used as a last resort, as organic approaches are more environmentally friendly. The seeds survive in soil for more than 10 years. Harvest Seeds. Bull thistles are biennial and only bloom every two years. Milk thistle has a mild flavor that turns bitter as the plant matures. Cultivation and tilling can also be effective to control bull thistle. What is bull thistle? Bull thistle prefers sunny, open areas and can tolerate a wide range of conditions, from moist to dry soils, and is typically found in disturbed areas such as roadsides, trails, logged areas, vacant land, pastures and cultivated land. principle to bull thistle control is preventing seed production. The seeds are short‐lived and most on or near the soil surface do not remain viable for more than a year. A single field thistle seed with pappus. The plant has colonized much of North America and is a pest plant in the garden and in agriculture. Remove stems from site if plants are cut or pulled with flowers. (When we first moved here, the place was overrun with thistles. Bull thistle is a Class C Noxious Weed in Washington, first listed in 1988. Bull thistle plants are native to Western Asia, North America and parts of Europe. Bull thistle may also dominate forest clear cuts and reduce growth of tree seedlings. As the stem gets thicker, the wings start drying and disappearing. Thistles that are actively growing and in the rosette to flower stage of growth can be controlled with a post-emergence herbicide application. Nyjer seed also commonly known as niger or thistle seed is popular with many backyard bird species, particularly seed-eating birds and winter finches. If the bull thistle population is large enough to support a good sized population of this insect, it can be an effective way to reduce seed production of the bull thistle. Bull thistle can reach a height of 3 feet. Seeds germinate rapidly and are spread by wind. 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.Prickles can also occur all over the plant – on the stem and on the flat parts of the leaves. Not only does the goldfinch pull the seeds out to eat; it also uses the thistle down (the pappus) to line its nest. Thistle seed bird food is great for year-round feeding. Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. Caution: Plants have spines along leaves and stems. Cultural/grazing: Bull thistle is not as competitive in a well-managed pasture and regular cutting combined with good pasture management can reduce bull thistle to a manageable level. Most King County offices will be closed on December 25, for Christmas Day. Bull thistle thrives in sunny areas in a variety of soil types and conditions. Stems. Cutting off only the flower stalks will merely make the plant sprout another shoot; also, cut flower stalks left on the ground are likely to produce viable seeds, even after they are cut. Urophora stylat… The white pappus “parachute”or “hair”, is about ¾ inch long (20+ mm). Cirsium vulgare, the spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus Cirsium, native throughout most of Europe (north to 66°N, locally 68°N), Western Asia (east to the Yenisei Valley), and northwestern Africa ( Atlas Mountains ). Sign up for our newsletter. The seeds are one tenth to two tenths of an inch long, with plume-like bristles on the tip. It has a deep taproot, which makes manual pulling a challenge. It is a prickly biennial that grows freely in disturbed soils, pastures, ditches, roadsides and unmanaged spaces. Seeds usually germinate in the spring and fall. What's more, one individual plant can produce up to 5,000 seeds, making it quite prolific. An individual plant can produce up to 100,000 seeds. …and without the pappus. Seeds usu-ally germinate in the spring and fall and have a 95% germination rate. Each plant has a fleshy taproot. Again, that big Bull Thistle on the Hilton Pond Center roadside formed 50-plus flower heads--each capable of producing 250 seeds--meaning just that individual plant is theoretically capable of disseminating 12,000 seeds! As mentioned earlier, they thrive in disturbed soils.) Thistles are found throughout the United States and Canada. Reproduction is performed only through the seeds. Comparatively, Canada thistle is a perennial that reproduces through underground rhizomes and wind-blown seeds. This plant bears leaves that end in extended, very sharp thorns and are beige in colour. Musk thistle and bull thistle are biennials causing major problems in perennial grass crops including pastures, roadsides, conservation reserve and fence rows. After hatching, the larvae burrow into the seed-prodcuing tissues to feed, forming galls and reducing seed production. Around here it’s not too hard to find a thistle plant, and our main variety is common Bull Thistle (Cirsium vulgare). They are dispersed by wind. This insect will not get rid of the bull thistle, however, just reduce its impact. Mechanical control: Mowed thistles will produce new branches from basal buds but close cutting or cutting twice per season will usually prevent seed production and reduce the population over time. Bull thistle might be confused with native thistles as well as more serious noxious weeds such as milk thistle, a Class A noxious weed in Washington, and Canada thistle, a Class C noxious weed that is much more difficult to control. This thistle plant I’m testing is a bull thistle, and the spines are huge and rigid. For widespread control, mowing twice per year has been effective in reducing the population by preventing seed heads. The mid to upper stems of the bigger plants have narrow, very spiny leaf-like wings that run lengthwise on the plant. Carduus nemoralis E.H.L.Krause. The roots of this plant are taproots. Because control is not required in the county, it is on the list of Non-Regulated Noxious Weeds for King County. However, it has been shown to have limited effectiveness. Bull thistle reproduces only by seed. The stubborn plant can arise like Lazarus from the ashes if hand pulling leaves behind any of the root. Bull thistles (Cirsium vulgare) are exactly that – bullish. Wildflowers Of WisconsinWild… The flowers are produced at the ends of the tangled stem growth and last for several weeks before producing tiny striped seeds capped with white downy hairs. Spiny-winged, hairy stems elongate during the second year, often branched up to 7 feet tall. Hand-pull and dispose of flowering plants in trash to prevent seed spread. Overgrazed pastures are susceptible to bull thistle encroachment, and it can sometimes form dense stands that reduce productivity and stocking levels. Writer Bio. If cut too early before flowering, plants may re-sprout and flower again that season. Bull thistle reproduces only by seed, and indi-vidual plants set seed only once before dying. All biennial thistles considered noxious are native to Europe or Eurasia, and were introduced into North America as seed contaminants. Other Info: Similar to Canadian thistle, the more robust bull thistle was introduced to the United States in the 1800’s from Europe and Asia, and has now spread to 42 states, being declared a noxious weed in 16. This thistle produces a lot of seeds that have small feathers and are fixed to the base by means of a ring until they mature. After spraying, wait two weeks or more to give the herbicide time to work. Bull thistle plants can produce approximately 7000 seeds. Those flies lay eggs in developing bull thistle flower buds. Bull thistle control can be manual or chemical with an emphasis on seed control. Bull thistle can be controlled most effectively by cutting the root several inches below the ground. The goldfinch is particularly attracted to the thistle. Casual removal with this method is likely to leave behind the genesis of a plant in spite of the foliar amputation. Pull thistles before they bloom so their seeds don't spread in the wind. Weedy characteristics: Bull thistle is highly competitive and aggressive, and forms dense colonies that choke out native vegetation important to wildlife and pollinators. Seed/ Fruit Size: The cleaned seed itself (no pappus) is about 3/16 inch wide (2 mm) and 13/32 inch long (4 mm) and reminds me of a banana pepper in shape. We can provide advice on how to control bull thistle, but there is generally no legal requirement to do so. If your site has animals grazing, please read instructions carefully on grazing restrictions. Seeds spread by wind and have high dispersal rates. Bull thistle rosette (left). Learn how to get rid of bull thistle and prevent this prolific weed from taking over your garden. A common type of weed most homeowners and gardeners hate to see sprouting up on their turf is thistle. Bull thistle grows in disturbed areas such as pastures, roadsides and ditches. Seeds buried at a depth of 5 inches may remain viable for up to three years. The plant has the ability to produce around 5,000 seeds in a season. A tough weed to kill, the flower heads on thistles possess thousands upon thousands of thistle seeds, which allows them to spread at an exponential rate both above and below the soil. Chemical treatment is most effective on the first year rosettes of bull thistle plants. Seeds on the surface typically do not survive for more than a year; seeds buried may remain viable for up to three years. These bur-like seeds cling to animals, pant legs, machinery, etc. Tall Thistle lives up to its name, growing up to seven feet in height. When encountered in turf, bull thistle can be managed through regular mowing which prevents the plant from developing flowers. Digging the plant out with a spade or hori hori is the best approach to mechanical bull thistle control. Melissa King began writing in 2001. See the biological control page for more information. Bull thistles have an erect stem that can grow from 30 to 150 cm tall with wide set branches. Of course, your battle with the plant will only be as effective as your neighbors because of the travel ability of the downy seeds. Bull thistle seed production is impacted by the seedhead gall fly, Urophora stylata. The flowers are located at the end of stems covered in spiny hairs. Also, goats and sheep have both been used for grazing management of bull thistle. In addition to attracting finches, it also attracts chickadees, siskins, and other small songbirds. Seeds remain viable in the soil for up to 10 years. Clemson University. Contaminated hay is a primary means of spread of this species so be careful to purchase weed free hay or watch closely for new plants in the areas hay is kept or spread. It has a central taproot so does not spread by rhizomes. It is a prickly biennial that grows freely in disturbed soils, pastures, ditches, roadsides and unmanaged spaces. Herbicide Use. The main stem of this wild edible is firm and thorny. If only one cutting a year is possible, cut when plants are in bud for best results. Knowing which birds eat Nyjer can help birders choose the best birdseed and appropriate feeders for their backyard flock. Read about the presence and treatment of bull thistle after the 2012 Reading Fire. In summer the plant grows a scented flower that resembles a spiny globe topped with fringed pink petals. 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There are several herbicides that are effective on bull thistle, but it is important to carefully match the product with your site, local conditions and regulations, and other weed and land management issues, and always follow the label directions for the product you are using. 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. When roasted, the thistle's seeds serve as a coffee substitute. Seedling: Cotyledons of the bull thistle are oval-shaped, being broadest at the apex. This gall fly’s larvae induce and feed on gall tissue in the developing bull thistle seedhead, reducing seed production up to 60%. Flowers and fruit. and get spread around with abandon. The outer rim of the flower is green and spiny itself, and contains many disk shaped flowers that are reddish-purple. Clemson, SC. In agricultural situations, the introduction of a bull thistle seed head gall fly has been proposed as a biological agent. The hairy, prickly leaves overwinter to develop stems and branches of up to 2 feet in spring. It's no wonder this species might take over a pasture in a few short years. The early leaves of its young plant are also oval with a spine-like fringe. Pasture Thistle, also called Field Thistle, is a biennial or short-lived perennial. By: Bonnie L. Grant, Certified Urban Agriculturist. There is also a weevil that is an effective control agent, but it can also affect desired thistle species. Flower Seed Head. Bull thistle (Cirsium vulgare) is a plant that is related to the sunflower family but has none of the charm and beauty of those sunny-nodding flower heads. Contaminated hay is a primary means of spread of this species so be careful to purchase weed free hay or watch closely for new plants in the areas hay is kept or spread. Bull thistle is a biennial plant that can grow up to six feet tall. Biennial thistles spread only by seed (achenes) that are produced in great number by all the noxious species, ran… To contact staff, see the Noxious Weed Control Program Directory, send an email, or call 206-477-WEED (206-477-9333). Pennington Premium Thistle (Nyjer) Bird Seed is the single best seed for attracting colorful finches, including Goldfinches. Biennials require portions of two growing seasons to reproduce. Mowing can be effective, but make sure the plants do not flower. Bull thistle is distasteful to most grazing animals, giving the thistle a competitive edge. Sign up to get all the latest gardening tips! It is a free-seeding weed with a prickly demeanor and rapid spread. In this video, I show you how to identify Bull Thistle Seeds in the Fall. For more information, see Noxious Weed Lists and Laws or visit the website of the Washington State Noxious Weed Control Board. The Bull thistle was used by early humans as a warm medicinal tea. Cirsium silvaticum Tausch. https://www.fs.fed.us/database/feis/plants/forb/cirvul/all.html Chemical control: For information on herbicides and recommendations for control, please see the Pacific Northwest Weed Management Handbook. The species name, altissimum, means “the tallest.”It is a biennial with a tap root, not a rhizomatous root like some agressive, non-native thistles (i.e. Bull thistle starts life as a spiny leaved rosette. Encourage bull thistle seed-head gall flies to live and breed on bull thistle plants. For this reason, bull thistle removal is a priority among farmers and meticulous gardeners. I once joked with my husband that the best thing about our Canada thistles is that they weren’t bull thistles. Do not leave cut stems of flowering bull thistle on the ground because they are likely to form viable seed after they are cut. Weed Photos: Courtesy of Dr. Lambert McCarty. The next emerging leaves … The plant has colonized much of North America and is a pest plant in the garden and in agriculture. Because bull thistle is so widespread, property owners in King County are not required to control it and we are not generally tracking infestations. For grassy areas, it is best to use a selective broadleaf herbicide to keep the competitive grasses intact. Roots. Soil disturbance can stimulate germination and a flush of new plants. These attach themselves to any object that brushes against them. They grow from seed the first season as a rosette (a taproot with a cluster of leaves on the soil surface). Most seeds germinate rapidly, usually in the spring and fall. The leaves of a bull thistle are large, woody and are flatted and basal rosette during their firs… Bull thistle control can be manual or chemical with an emphasis on seed co… The types of sprays used in agricultural scenarios are dicamba, glyphosate or 2,4D. Prevention: Bull thistle only reproduces by seed so prevention of seeding and takign care not to spread seeds are key to preventing new infestations. The seeds are wind dispersed, and they’re liable to pop up in any corner of our land that gets decent sun. The seed of bull thistle remains viable for only a few years, but structures similar to those on dandelion seeds enable new bull thistles to drift downwind into the park. Prevention: Bull thistle only reproduces by seed so prevention of seeding and takign care not to spread seeds are key to preventing new infestations. Bull thistle spreads by seeds. The Bull thistle also provides seeds to granivores (consumers of grains and seeds) such as goldfinches. More more effective control, cut plants with a sharp shovel at 1-2 inches below the soil surface prior to flowering. Large individuals may produce tens of thousands of wind-dispersed seeds. On smaller plants, the whole stem and branches are spiny-winged. Bull thistle - Cirsium vulgare or Canada thistle - Cirsium arvense).As a biennial it reaches flowering stage in year 2 before dying off. The bull thistle is a biennially growing plant. Bull thistle seeds are numerous and straw-colored. Bull thistle (Cirsium vulgare) is a plant that is related to the sunflower family but has none of the charm and beauty of those sunny-nodding flower heads. Take care to remove the entire fleshy taproot for best results. Even horses will help by picking out many of the nectar-rish flowers and eating them before they go to seed. In order to reduce the seed population, cut off the seed head and tuck it into a sack to keep the fluffy seeds from dispersing. Red to purple, usually solitary flower heads consisting of only disk flowers are … Find more gardening information on Gardening Know How: Keep up to date with all that's happening in and around the garden. Coarse hairs of bull thistle (right). Become a certified small business contractor or supplier, Find certified small business contractors and suppliers, Washington State Noxious Weed Control Board, Pacific Northwest Weed Management Handbook, King County bull thistle best management practices, University of Washington Burke Museum Herbarium Image Collection - Cirsium vulgare, Branching, erect biennial, 2 to 6 feet tall, Rosettes form in first year, flowering stems the second, Long, sharp spines on the leaves at the midrib and the tips of the lobes, Leaves are deeply lobed and hairy - there are coarse hairs on leaf tops, making leaf feel rough to the touch, and woolly hairs on the underside, Leaf bases extend down onto stems and form spiny wings along the stems, Flower heads are "gumdrop" shaped and spines extend all around the base of the flower heads. Biological control: The bull thistle seed head gall fly (Urophora stylata) lays eggs on closed flower buds in June and July. 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