Saturday, 04 July 2009 08:56

Houndstongue (Cynoglossum officinale) is a member of the Borage family.  It is a biennial that was introduced from Europe.  It reproduces by seed and appears as a leafy rosette in its first year.   During the second year of growth the plant grows 1 ½ to 3 feet high with reddish-purple flowers.  Houndstongue is commonly known as the "Velcro weed" because of its small nutlets that cling to (and are rapidly spread by) people, domestic animals, wildlife and vehicles.  Houndstongue grows on ranges, pastures, trails and roadsides and is toxic to horses and cattle, as it contains alkaloids that may cause liver cells to stop reproducing. Plants often emit a musty odor.

Mechanical Control:
Physically remove the plant at flowering or in early seed formation.  You can pull or dig these weeds out.  Be sure to bag and destroy the plant (e.g. bury in sterile landfill) so seeds do not mature on it after you pull it.

Chemical Control:
Apply herbicides during the pre-bud stage or in the rosette stage.  Pre-bud occurs in the spring or early summer and the rosettes form in late summer and early fall.  Surfactants (“SURFace ACTive SubstSANCES) are recommended to help the herbicide stick to and get absorbed by the hairy leaf.

 For additional information, contact Pitkin County Land Management at 920-5214 or the City of Aspen Parks Department at 429-2026.

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