HPIPM:Houndstongue

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Asteranae
Order	Boraginales
Family	Boraginaceae
Genus	Cynoglossum

Scientific Name

Cynoglossum officinale

Common Name

houndstongue

Houndstongue (Cynoglossum officinale)

Author: Jim Jacobs, Plant Materials/Invasive Species Specialist, USDA-Montana NRCS.

Adapted from the USDA NRCS Montana Invasive Species Technical Note “Ecology and Management of Houndstongue (Cynoglossum officinale L.)”

Identification and Life Cycle

Houndstongue (Cynoglossum officinale) is a biennial or short-lived perennial in the forget-me-not family (Boraginaceae). Flowering stems grow to a height of 1 to 4 feet tall. The flowers are dull reddish-purple. Houndstongue seeds are large and contain four nutlets. The entire nutlet is covered with prickles barbed at the tip that attach to the fur of animals and the clothing of people. Houndstongue seedlings develop into rosettes during the first year. Rosette leaves can grow to 4 inches long with entire margins and are covered with soft hairs. Houndstongue plants develop thick, black, branching taproots that can grow to depths of greater than 3 feet in the first year.

Habitats

Houndstongue occurs on rangeland, pastures, abandoned cropland, roadsides and waste places, at the borders of woods and forests, and along riparian areas. It is found on rocky, sandy, loamy, and calcareous soils.

Impacts

Populations of houndstongue displaces forage species and decrease grazing capacity of rangelands and pastures. Houndstongue has not been a problem in cultivated fields. Nutlets reduce the value of wool and cause irritation, eye infection, and behavioral problems in cattle. Poisoning has been reported in cattle, horses, and sheep.

Biology and Ecology

Houndstongue seedlings emerge in March and April and form a rosette in the first growing season. Rosette leaves grow from the root crown in the second year until the formation of the flower stem in May. Houndstongue flowers from May through July. A single houndstongue plant can produce 50 to 800 seeds. Long-distance dispersal of houndstongue seeds occurs when seeds attach to the fur of animals.

Management Approaches

Management should target the flowering stage of growth to prevent seed production. The potential for long-distance immigration of seeds often makes houndstongue a long-term management problem, even where it has been locally eradicated.

Biological Control

No classical biological control agents have been released in the U.S. However, two agents have been released in Canada, the root-mining flea beetle (Longitarsus quadriguttatus) and the houndstongue root-mining beetle (Mogulones cruciger).

Mechanical and Cultural Control

Prescribed burning in late summer and early fall may reduce the spread of houndstongue. Houndstongue plants can be pulled at any time during the growing season. A single shallow tillage will kill rosettes and root crowns.

Chemical Control

Herbicides should be applied during the rosette stage or prior to the bud stage. Surfactants are required due to the hairiness of the leaf. Follow herbicide label instructions and recommendations.

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=Houndstongue