The Enemy: Houndstongue (Cynoglossum officinale)

Strategy: This biennial plant grows from 1 to 4 feet tall and reproduces by seed. Each plant will send up four to six shoots. The leaves are rough, long resembling a hound’s tongue and are somewhat hairy. The flowers are reddish-purple and form four prickly nutlets, each about 1/3 inch long with barbs that allow it to cling onto clothing, fur, shoelaces and anything that brushes against it. Houndstongue is toxic to animals as it causes liver damage. It is mainly spread by wildlife and livestock, but we can find it anywhere humans have visited.

Attack: One of the ways animals eat it is by indirect ingestion through weedy bailed hay and alfalfa. The seed can catch a ride on animal’s fur or feathers and be carried for many miles. It is extremely mobile and once established out-competes native habitat. It gets particularly dense in riparian areas near water, as there is an abundance of moisture and it gets rubbed off animals in the shade by the branches. Because the seed is cased in the hard barbed shell, it can last seven to 10 years in the soil. Protecting our backcountry trails is a must.

Defense: As this is an biennial, mechanical control can be effective. If you decide to dig it out with a shovel, make sure that you get at least 3 inches of the root. It’s been difficult finding an insect for biological control that is allowed in the country as this plant is in the borage family, and we have a few native borages insects like. Many herbicides are available. Telar XP, Opensight, and Milestone work extremely well. Treatments can be in spring or fall.

To learn more, call Bonneville County Weed Superintendent Jeffrey Pettingill at 208-529-1397 or email