HOUNDSTONGUE — Cynoglossum officinale L.

Boraginaceae — (Borage Family)

Houndstongue is a biennial growing one to four feet tall and reproducing by seed. Leaves are alternate, one to twelve inches long, one to three inches wide, rough, hairy, resembling a hound’s tongue and lacking teeth or lobes. Flowers are reddish-purple and terminal. The fruit is composed of four prickly nutlets each about one-third inch long.

Houndstongue was introduced from Europe. It forms a rosette the first year and sends up a flowering stalk the second year. It may be found in pastures, along roadsides and in disturbed habitats. The nutlets break apart at maturity into bur-like seeds and attach to clothing, fur of pets, and camping gear. 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.

Growth Habit: Biennial, spread by seed. Rosette is formed on ground 1st year, flowering stalk elongates 2nd year.

Leaves: Velvety to touch. Basal – broad, lance-shaped. Upper – narrower, pointed, clasping stem.

Stems: Heavy, erect, usually branched above, to 3` tall.

Flowers: Dark red, rarely white, ¼" diameter in terminal clusters.

Roots: Taproot.

Seeds: Fruit consists of 4 flattened bur-like nutlets, each ¼" long with short barbed appendages.

Other: Burs attach to hair and fur of animals and are easily transported.

(Courtesy of Weeds of the West)

Control Strategies:

Chemical and mechanical controls are most effective during the first growth year or rosette stage. Flowering or seed–bearing plants may be dug up, so long as extreme caution is taken to collect all seeds. NOTE: It is highly likely that a person’s socks, hiking boots and clothing, as well as pets, collect this seed when walking or hiking – be sure you pluck these seeds and dispose of them in a trash receptacle. Do NOT throw them back down on the ground. Cutting seed stalks and bagging them for removal from the site prevents new seed from getting to the soil and significantly reduces next year's crop. The best herbicide for Houndstongue is Plateau at 10 to12 ounces per acre. Add methylated seed oil surfactant to the mixture at the rate of 1% by volume. This has great burn down on small rosettes. No herbicides are outstanding on bolting plants. Escort and Telar are reported to eliminate seed viability if sprayed before the seed is mature.

To learn about biological control agents for Houndstongue visit this link.