Houndstongue (Cynoglossum officinale)

Houndstongue is a biennial growing 1 to 4 feet tall and reproducing by seed. Leaves are alternate, 1 to 12 inches long, 1 to 3 inches wide, rough, hairy, and lacking teeth or lobes. Flowers are reddish-purple and terminal. The fruit is composed of 4 prickly nutlets each about 1/3 inch long.

Houndstongue was introduced from Europe. It forms a rosette the first year and sends up a flowering stalk the second year. The leaves are rough and resemble a hound’s tongue. It may be found in pastures, along roadsides and in disturbed habitats. The nutlets break apart at maturity and cling to clothing or animals. Houndstongue is toxic, containing pyrrolizidine alkaloids, causing liver cells to stop reproducing. Animals may survive for six months or longer after they have consumed a lethal amount. Sheep are more resistant to houndstongue poisoning than are cattle or horses. Horses may be especially affected when confined in a small area infested with houndstongue and lacking desirable forage. Therefore, ranges and pastures should be maintained to encourage production of grasses and high quality forage.

If you would like more information, email MWCA at acamm@montana.edu with your questions. A weed control expert will be happy to answer your questions.