Hound's tongue (Cynoglossum officinale)

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A biennial, with a thick, deep taproot, that has two distinct growth phases, a first year rosette vegetative growth phase, followed by a second year reproductive flowering phase. Grows to 1.2 m tall. Leaves are oblong with numerous soft white hairs on both surfaces. They have prominent veins and are said to look like a dog’s tongue. Flowers range in color from dull red to burgundy. Each flower develops seed clusters containing four (sometimes three) nutlets. Fruits are flat, teardrop-shaped, and have a hard spiny husk with barbs. Protruding barbs adhere to fur or fleece of wildlife and livestock, and human clothing. CAUTION: Poisoning occurs when animals consume sufficient quantities of hound’s-tongue with high pyrrolizidine alkaloid concentrations.

Key Identifiers
  • Leaves are tongue-shaped, hence the name, and are attached closely to the stem with the uppermost leaves clasping the stem.
  • The fused petals of the flower are reddish-purple.
  • Seeds are contained in the prickly four-lobed nutlets that cling to fur and clothing.
Location in Canada
Hound’s-tongue is located in all Canadian provinces, excluding Newfoundland and PEI.

Alberta Invasive Plants Council - HoundsTongue

Similar species
Verbascum thapsus - In the rosette stage, can appear similar to common mullein (Verbascum thapsus), however hound's tongue leaves are darker green, droop, and have coarser hairs on them. Both are Noxious in the Alberta Weed Control Act.

Hackelia spp. & Lappula spp. -The flowers are light blue to white and the fruits have spines on the margins only.
Cynoglossum boreale -The native species Cynoglossum boreale is more commonly found in eastern North America(only 1 report in AB). It lacks leaves on the flowering stem and has white or blue flowers.

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For more information about the content of this document, contact Chris Neeser.
This document is maintained by Shelley Barkley.
This information published to the web on March 23, 2012.
Last Reviewed/Revised on August 21, 2018.