Ecology and Management of Common Tansy (Tanacetum vulgare L.)

Invasive Species Technical Note Number MT-18

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Invasive Species Technical Note Number MT-18 (PDF; 676 KB)

February 2008

Abstract

Common tansy is a robust perennial forb that grows up to five feet (1.5 meters) tall from large woody rhizomes. It produces large, aromatic, fern-like leaves and clusters of small button-like yellow flowerheads. It is a member of the sunflower family (Asteraceae) with origins in Eurasia and is normally found along roadsides and railroads, fields and pastures, ditch banks, riparian areas, and other moist places. Volatile oils produced in the leaves and flowers deter grazing by cows and horses. Historically, the oils have been used medicinally and the literature is fairly rich in common tansy’s pharmacological characteristics, but scant in its invasive ecology. Escaped cultivated plants brought to North America as early as the 1600’s are most likely the original sources of common tansy infestations. Populations often grow in thick clumps that crowd out grasses, forbs, and shrubs resulting in reduced livestock forage and wildlife habitat (see Figure 1). It is listed as a Category 1 noxious weed in Montana and as a noxious weed in Wyoming.

Figure 1. A dense population of common tansy growing along a creek in Gallatin County, Montana.

Metsulfuron and clorsulfuron are the most effective herbicides for controlling common tansy when applied to actively growing plants before bloom at 0.5 ounces/acre (Escort®, Cimarron®, or Telar®) or metsulfuron plus chlorsulfuron (0.5 ounces Cimmeron® X-tra). Tillage will control common tansy on cropland in rotation but follow-up tillage or herbicide applications (glyphosate: 2 qts./acre) may be needed to control plants regenerating from seeds or rhizomes. Tillage will also spread rhizomes. Persistent hand pulling and grubbing that removes the rhizomes will reduce small-scale populations. Mowing before bloom and repeated whenever plants initiate flowering will reduce seed production and over time may reduce populations where there are competitive grasses. One study suggests common tansy populations can be reduced using sheep or goat grazing, but animals should be removed four to six weeks before breeding to avoid reproductive problems. There are no biological control insects available for management of common tansy. Applying practices that encourage competitive desired plants such as forage harvest management, nutrient management, and prescribed grazing will improve control procedures and reduce the spread of common tansy.

Plant Biology

• Taxonomy
• Identification
• Life History
• Competitive Interactions
• Habitat, Spread and Impacts

Management

• Herbicidal Control
• Hand Pulling, Mowing and Tilling
• Prescribed Burning
• Grazing Control, Cultural Control and Biological Control
• Re-vegetation
• Integrated Pest Management

References

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Last Modified: 11/10/2011