Abstract

Tall buttercup is a perennial forb native to central and northeastern Europe where it is a weed of old pastures and hay meadows. Stems grow up to three feet tall (about one meter) with deeply-lobed leaves (three- to five-lobes) on the lower stem and leaves reduced in size with three to four narrow segments on the upper stem. Flowers are bright yellow and about one inch (2.5 centimeters) in diameter. (See Figure 1.) Tall buttercup reproduces both by seed production and by short splitting rhizomes. First found in the Bozeman area in Gallatin County in 1916, it currently is reported from 23 counties in western and central Montana. Ingestion of tall buttercup by grazing animals causes blistering of the lips and tongue, intestinal disorders, and potentially fatal ventricular fibrillation and respiratory failure as a result of the enzymatic breakdown of ranunculin, a glycoside toxin.

Tall buttercup is listed on the Milestone® and Clarity® herbicide labels. It can also be controlled using the non-selective herbicide glyphosate. Consult with your extension agent or county weed coordinator for herbicide recommendations in your area. Always read and follow label instructions. Currently there are no biological control insects available to manage tall buttercup. However, research shows the Sclerotinia fungus reduced dry weight in dairy pastures. Mowing may reduce seed production. Tall buttercup generally increases under grazing, including sheep grazing. Fertilization of pastures does not affect tall buttercup, but it may promote grasses.

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Download this two page publication today.   Learn how to tell spotted knapweed from brown knapweed.

MWCA has pages devoted to identification of the knapweeds  listed on the Montana Noxious Weed list:  Russian Knapweed, Spotted Knapweed, Diffuse Knapweed and Yellow Starthistle.

What is going on?

There is a growing concern in western Oregon, and that concern is Tansy Ragwort. It seems to be rearing its ugly head (maybe pretty to some) in numerous areas in western Oregon. People want to know what to do about it. Why have the biocontrol agents like the cinnabar moth and flea beetle failed to control it? Will we have economic losses to our livestock again, as occurred in the 1960-70s?

Oregon enjoyed a long-term success in the mid-1980s through 2005 of not having a lot of tansy ragwort around, to the tune of 5 million dollars a year in economic benefits to Oregon agriculture. Tansy ragwort is a biennial plant in the sunflower family that was unintentionally introduced into Oregon in the early 1920s, and within 30 years, became a regional problem, killing thousands of livestock animals – mostly cattle and horses, and contaminating pastures and hay. By the 1970s, many pastures, hillsides, and log clearings were invaded and heavily infested by tansy ragwort. Tansy is mostly a weed that gets a foothold in plant communities that have been disturbed, either by grazing, logging, construction, fire etc. Unless you have livestock, tansy is more of a symptom of a problem than a problem. The Oregon legislature commission the Oregon Department of Agriculture (ODA) to implement a biological control program to control tansy ragwort. Three insects, the cinnabar moth, a flea beetle, and a seed head fly were introduced from 1960-1971. These insects are natural enemies of tansy ragwort that were tested for host specificity and imported from tansy’s homeland in Western Europe. Once they were established in Oregon, ODA began an intensive redistribution program, collecting and releasing millions of the biocontrol agents at infested sites throughout the state. By the mid-1980s, tansy infestations were in sharp decline and cattle deaths were reduced by more than 90%.

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ST. JOHNSWORT (HYPERICUM PERFORATUM L.), also known as goatweed and Klamath weed, is an economically important pest in temperate regions worldwide. Although used as a possible natural antidepressant, St. Johnswort causes considerable ecological and economic losses. In addition to displacing desirable plants that are important for wildlife habitat and domestic livestock forage, St. Johnswort also poses risk of poisoning grazing animals. Correctly identifying St. Johnswort and understanding the plant’s life cycle and growth requirements are important for selecting management strategies that will effectively suppress St. Johnswort populations and promote healthy, desired vegetation.

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Flowering rush is a non-native aquatic resembling a large sedge that grows along lake shores and slow moving water bodies. In Montana it was recorded in Flathead Lake in 1964 and has spread to Thompson Falls, Noxon Reservoir, Cabinet Gorge, portions of the Flathead River, and the Clark Fork River. Prolific growth in irrigation ditches reduces water availability, and dense stands in previously unvegetated areas inhibit boating, fishing and swimming. Minor disturbances cause the roots to fragment, providing long distance dispersal. At this time, control methods are limited. Hand digging has led to mixed results as rhizomes fragment easily, increasing dispersal. Studies on chemical control options are ongoing.

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Abstract

A close relative of spotted knapweed in the Asteraceae taxonomic family, diffuse knapweed is typically biennial, reproducing exclusively by seed. It forms a rosette with a central crown and tap root in the juvenile stage and a single upright stem one to three feet (0.3 to 0.9 m) tall with numerous spreading branches at maturity. White (occasionally purple) flowers are borne in heads with spiny bracts (see Figure 1). It is generally found on more arid sites than spotted knapweed. Native to the Mediterranean region, diffuse knapweed was first recorded in Montana from Mineral County in 1951 and by 2008 had been reported from 39 of Montana’s 56 counties. Its dense, spiny overstory reduces the availability of desirable forage plants to livestock and wildlife, and grass production can be reduced by over 90% in heavy infestations.

Declines in diffuse knapweed populations in western North America have been attributed to the lesser knapweed flower weevil (Larinus minutus), one of 14 approved biological control insects it is host to. Herbicidal management can best be achieved by application of any of the following chemicals at the rosette to bolt stages: aminopyralid, clopyralid, dicamba, picloram, and 2,4-D. Grazing management using sheep or goats should be applied during the rosette and bolt stages before the formation of spiny flowerheads, and animals should be removed when 50% of grass forage has been utilized. Tillage can be used to remove plants and release the seed bank. Persistent hand pulling and grubbing may be practical on small scale infestations. Diffuse knapweed re-sprouts following fire, including intense wildfire. Cultivating and re-vegetating competitive plants will improve the longevity of control applications and reduce re-establishment from the seed bank.

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Here is a small excerpt:

If the commonly used term “war on weeds” seems overly dramatic, consider this: Noxious weeds today infest more than 130 million acres of the United States.

Each year they overrun an additional 1.7 million acres, invading an estimated 6 square miles of Bureau of Land Management (BLM) and U.S. Forest Service (USFS) lands every day. Weeds have infested more than 7 million acres in national parks, including Glacier and Yellowstone. Harmful invasive plants are a major scourge of agriculture, which declared the “war.” Each year noxious weeds cost Montana producers $100 million in control expenses and crop production losses, according to the Montana State University (MSU) Extension Service.

Read the complete article on the Montana Outdoors magazine website.

I. Introduction: History/Identification/Threat for Russian Olive

A. Russian Olive History: Russian olive (Elaeagnus angustifolia L.) is a member of the Oleaster family. Russian olive originated on the European Continent and ranged from southern Europe to western and central Asia (Little 1961). Russian olive was introduced to the United States in the early 1900’s. Tolerant to diverse site conditions, Russian olive has been planted as an ornamental (Little 1961), and used extensively in shelterbelts in the drier regions of the Great Plains and Rocky Mountains (Read 1958). In Montana, east of the Continental Divide, Russian olive trees have been used in shelterbelts, windbreaks, wildlife habitat, ornamentals and for wildlife habitat. Plants that have naturalized thrive along riparian corridors, irrigation delivery systems, pastures, saline affected areas and some wetland sites.

B. Russian Olive Identification: Russian olive is a large, thorny, perennial deciduous shrub or small tree (up to 40 feet). The leaves are alternate and simple, elliptical to lanceolate in shape, 1 to 3 inches long and ½-inch in width, scaly on the top and silvery and scaly on the bottom, dull green to gray in color. Stems may be thorny. The bark appears smooth and reddish brown to gray in younger trees and becomes unevenly rigid, wrinkled and graying in color as it matures. The fruit is berry-like, approximately ½-inch in length, dry, mealy, sweet, and edible.

C. Russian Olive Threat: Russian olive infestations threaten native plant communities in riparian areas and grasslands, as well as irrigated pastures and hay land. Russian olives have been identified along all of the watersheds in eastern Montana. Along riverine areas native cottonwood and willow species are being replaced by Russian olive through competition and succession. Russian olive grows relatively quickly and develops a dense canopy; preventing shade-intolerant native vegetation from establishing. Katz and Shafroth (2003) report that Russian olive constitutes a new functional guild; it can establish beneath the canopy of native riparian trees and can form self-replacing stands. In addition, there are selective pressures from mammals. Lesica and Miles (1999) observed that beavers select cottonwood and willow over Russian olive to forage on; providing Russian olive plants an additional competitive edge over native woody riparian vegetation.

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Visit the MWCA Weed ID page for details about yellow starthistle. Contact your local weed coordinator if you think you find it in your area.  There may be a reward.