Identification and Control of INVASIVE and TROUBLESOME WEEDS in North Dakota
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W1411 (Revised Sept. 2018) Identification and Control of INVASIVE AND TROUBLESOME WEEDS in North Dakota Rodney G. Lym, Professor of Weed Science NDSU Department of Plant Sciences N.D. Agricultural Experiment Station NDSU Extension Revised and reprinted September 2018 his publication was made possible by collaboration of the author, North Dakota State University Extension and the TNorth Dakota Department of Agriculture, with funding from the U.S. Forest Service for printing. This publication is intended to help land managers properly identify and control noxious and invasive weeds found in the state. The current list of 11 noxious weeds are included, as well as species listed by various counties as noxious. Other species included are either invasive weeds found in bordering states with the potential to move into North Dakota or are commonly misidentified native species that do not require control efforts, such as the native thistles. Control recommendations are current at publication, but options change rapidly. Before beginning any management program, please consult with your local county Extension agent and/or weed officer for the latest chemical, cultural and biological control recommendations. Chemical control recommendations are updated annually and printed in the “North Dakota Weed Control Guide,” Extension publication W253, and are updated more frequently on the Web at www.ndsu.edu/weeds. For the latest in biological control options, contact the North Dakota Department of Agriculture and/or the local staff of the U.S Department of Agriculture –Animal and Plant Health Inspection Service in Bismarck. 2 WEEDS Absinth wormwood . 4 Baby’s breath . 6 Black henbane . 8 Chamomile, false and scentless . .. 10 Common burdock . 12 Common mullein . 14 Common tansy . 16 Dame’s rocket . 18 Downy brome . 20 Field bindweed . 22 Halogeton . 24 Hoary cress . 26 Houndstongue . 28 Knapweed, Russian . 30 Knapweed, spotted and diffuse . 32 Kochia . 34 Leafy spurge . 36 Milkweed, common and showy . 40 Narrowleaf hawksbeard . 42 Orange hawkweed . 44 Palmer amaranth . 46 Poison ivy . 48 Purple loosestrife . 50 Saltcedar . 52 Sowthistle, annual and spiny . 54 Sowthistle, perennial and marsh . .. 56 St . Johnswort . 58 Thistle, bull . 60 Thistle, Canada . 62 Thistle, Flodman . 66 Thistle, musk . .. 68 Thistle, plumeless . 70 Thistle, Scotch . 72 Thistle, wavyleaf . 74 Toadflax, Dalmatian and yellow . 76 Yellow starthistle . 80 3 ABSINTH WORMWOOD (Artemisia absinthium L.) 4 ABSINTH WORMWOOD State Listed Noxious Weed Why is this plant a concern? Absinth wormwood is a member of the sagebrush family, Absinth wormwood causes economic losses by reducing which is easily recognized by the strong sage odor. The available forage, tainting the milk of cattle that graze it, plant also is known as American or common wormwood, and medically as a pollen source for allergies and asthma. mugwort or madderwort, and wormwood sage. Unlike Absinth wormwood can reduce forage production severely other plants in the sagebrush family, absinth wormwood in pasture and rangeland and is especially troublesome dies back to the root crown each winter, with new shoots when land is overgrazed. Allergy sufferers should avoid emerging each spring. Absinth wormwood is grown in walking through absinth wormwood infestations when the herb gardens for the sage flavor of the leaves. The young plant is flowering in late July and August. flower heads are the source of aromatic oil used to prepare vermouth and absinth. The oil of absinth wormwood is also an active ingredient in antiseptic liniments. How do I control this plant? Identification and growth form: Chemical. A variety of auxin-type herbicides, including products that contain clopyralid Absinth wormwood is a perennial fragrant forb or herb. (Stinger, Transline or Curtail), dicamba The plant commonly grows 3 to 5 feet tall at maturity. (various), Milestone (aminopyralid), 2,4-D, Absinth wormwood is woody at the base and regrows from Tordon (picloram) and glyphosate (various), the soil level each spring from a large taproot. Leaves are will control absinth wormwood. These light to olive green, 2 to 5 inches long and divided two or herbicides should be applied when the plant three times into deeply lobed leaflets. Leaves and stems are is at least 12 inches tall and actively growing. covered with fine, silky hairs that give the plant a grayish Herbicides applied too early in the growing appearance. Flower stalks appear at each upper leaf node season generally result in poor control. If a and produce numerous yellow flower heads 1/8 inch in fall treatment is desired, the plants should be diameter, which appear from late July through mid-August mowed in early to midsummer to promote in North Dakota. Each fruit contains one seed, which is active regrowth and to improve herbicide less than 1/16 inch long, smooth, flattened and light gray- coverage. brown. These small seeds are scattered easily by wind, water and animals, and in hay. Absinth wormwood is a Cultural. Livestock generally will not graze prolific seed producer but also can spread by short roots. absinth wormwood except in early spring. The plant is most often found on dry soils, in overgrazed Mowing and cultivation do not control this pasture and rangeland, wastelands and roadsides. weed. Biological. No biological control agents or pathogens are available for this weed. 5 BABY’S BREATH (Gypsophila paniculata L.) 6 BABY’S BREATH County Listed Noxious Weed Why is this plant a concern? Baby’s breath is an ornamental plant of Eurasian origin Baby’s breath forms dense stands and displaces desirable introduced to the U.S. in the 1800s. The plant is a member grasses and forbs. Because of the large taproot and the of the Pinks or Carnation family and is used by the ability to produce millions of seeds in a small area, this floral industry as a filler in bouquets. The plant escaped plant is difficult to remove once it has established in an cultivation and now infests pasture and rangeland in area. Baby’s breath has been listed as a noxious weed in several areas of the West. several Western states. Identification and growth form: Baby’s breath is a perennial with widely branching stems. How do I control this plant? The plant often grows to 3 feet tall and is easily identified Chemical. Baby’s breath can be controlled by the presence of many small white flowers. The leaves with herbicides that contain metsulfuron occur in pairs of up to 4 inches long and end with a point. (Escort or Ally) applied during the bolt to The number of leaves decreases with increasing plant preflower growth stage. height and during flowering. The flowers are small, about 1/8 inch, and generally white and five lobed, often with a Cultural. Hand-pulling this weed is not purple midstripe. Flowering occurs from late June to late practical because of the large taproot. Baby’s August in North Dakota. breath has not become a problem in cropland that is cultivated. Seeds are black, with two to five contained in capsules, and resemble pepper. The seeds can germinate in 10 to 15 days Biological. No biological control agents or and plants grow rapidly. Each plant can produce 10,000 or pathogens are available for this weed. more seeds, which are spread when the branches dry, break off and are moved in the wind similar to Russian thistle and kochia. The plant has a large, deep taproot that allows it to grow well in dry and poor soil conditions. 7 BLACK HENBANE (Hyoscyamus niger L.) 8 BLACK HENBANE County Listed Noxious Weed Why is this plant a concern? Black henbane is native to Europe and was cultivated Black henbane contains alkaloids (hyoscyamine, hyoscine as a medicinal and ornamental plant. In 1670, the plant or scopolamine, and atropine) that have caused occasional escaped cultivation in the United States and became livestock poisoning. The plant is not usually grazed by sparingly naturalized by 1859. Black henbane has since animals unless more palatable forage is unavailable. All spread throughout much of the United States, particularly parts of the plant, including the seeds, contain the alkaloids in the Northeast, Midwest and the Rocky Mountains. that can be toxic to humans and animals if eaten. Even just Two alkaloids in black henbane tissues (hyoscyamine and smelling the flowers can cause headaches and nausea in scopolamine) are useful sedative or anti-spasmodic drugs some people. when used under controlled conditions. Identification and growth form: How do I control this plant? Black henbane is an annual or biennial plant that can range Chemical. Herbicides recommended for in height from 1 to 3 feet. Rosette leaves are alternate and black henbane control include 2,4-D, dicamba have petioles almost as long as the leaf blades. Stems of (various), glyphosate (various), metsulfuron mature plants are erect, leafy, thick, coarse and widely (Escort or Ally), Milestone (aminopyralid) branched. Leaves are alternate, oblong to ovate, coarsely and Tordon (picloram). Herbicides should toothed to shallowly lobed and grayish green. The foliage is be applied prior to flowering to prevent seed covered with fine, sticky hairs and has a foul odor. Flowers production. are funnel-shaped, five-lobed, brownish yellow with dark purple veins, and arranged in long, leafy, spikelike clusters. Mechanical. Hand pulling, cutting or digging Fruit of the plant is pineapple shaped, approximately 1 inch small infestations of black henbane can be long, and contains hundreds of tiny, black seeds. effective. Wear gloves and protective clothing when handling these plants. Disking or plowing Seeds germinate and develop a rosette with a large, whitish should be repeated annually because seeds can branched taproot the first growing season. During the persist in the soil for an extended period of second growing season, the plant bolts and flowers from time. June to August. The plant produces hundreds of seeds from July to October that can remain viable for five years Biological.