Photo courtesy of Mary Ellen (Mel) Harte, bugwood.org
Cynoglossum officinale L.
Scientific Name Synonyms:
Life Span: Biennial
Growth Characteristics: Houndstongue completes its growth over two seasons. During thefirst growing season it forms a low growing rosette. During the second season, the stem grows 1 ½ to 2 feet tall. Seedlings are usually strongly clustered around parent plants.
Flowers: The fused petals of the flower are reddish-purple, usually consisting of about 10 flowers, but can go as high as 35.
Fruits/Seeds: Seeds are contained within prickly nutlets that cling to clothing and animal fur. This is the main form of dispersal. Nutlets are four-lobed. Houndstongue produces 50-2,000 seeds per plant.
Leaves: In the rosette stage, leaves are softly pubescent, 4-12 inches long, 0.8-2 inches wide. Stem leaves (2nd year) are tongue-shaped, hence the name, and are attached closely to the stem with the uppermost leaves clasping to the stem. The leaves are generally broadest near the base and narrower towards the tip.
Stems: The stems which occur the second year areabundant, and stout, bearing leaves from base to tip, and are simple or branched at maturity. They grow 12-48 inches tall.
Roots: A thick, black, branching taproot.
Houndstongue invades irrigated and dry pastureland and disturbed areas such as roadsides, logging roads, and heavily grazed areas. In Utah, it may be found in sagebrush, pinyon-juniper, cottonwood, mountain brush, quaking Aspen, ponderosa pine, and spruce-fir communities. It is a minor component in Gambel Oak communities in central and northern Utah. It is found at elevations from 4880 – 9900 feet in Utah. Houndstongue is shade tolerant, but grows best in full sunlight if sufficient water and nutrients are available. The rosettes can withstand drought stress, delaying flowering stem growth until conditions are favorable.
Soils: Adaptable to many soil types.
Associated Species: Gambel Oak, Rocky Mountain Maple, Aspen, Ponderosa Pine, Cheatgrass, Bur Buttercup
Uses and Management:
Houndstongue is an opportunistic species that exploits conditions suitable for its establishment and growth. In the variable environment of dune habitats, houndstongue populations are usually in decline, and only in rare years are conditions favorable for growth and/or seed production. For this reason, one may see large fluctuations in population density in a single locality. As is typical of biennials, large population increases are observed following reproductive success and large decreases or even local extinctions following reproductive failure. Annual disturbances as well as absence of disturbance can be fatal for biennial plant development; therefore most habitats are only temporarily suitable for biennials. Grazed range provides an environment where gaps are repeatedly created and therefore suitable sites for establishment are usually available. Where it has established on disturbed sites such as roads and around old buildings, it may persist indefinitely, as is evidenced by its continued presence in abandoned mining towns in southwestern Montana, even after 45 to 77 years of recovery.
Houndstongue causes poisoning in horses and cattle. It contains various pyrrolizidine alkaloids (PAs), whose concentrations are highest during its rosette stage and decrease as the plant matures. PAs are known to cause liver damage or failure in livestock. Poisoning can occur when houndstongue is cut and dried with harvested hay, or when animals are confined to a small area lacking desirable forage. Most livestock poisonings occur from ingestion of contaminated hay or feed. The acute or chronic nature of poisoning depends on the PA concentration, amount eaten, and rate of ingestion. Any level of houndstongue contamination in feed should be considered potentially lethal for all livestock.