Working together to strengthen and support noxious weed management efforts in Montana.


MSU June Post – Biological Control

Saturday, June 30th, 2012


Biological control is a term often used to describe insects that help to control noxious weeds.   The June MSU Monthly Weed Post provides updated information about some of the agents currently available for leafy spurge, spotted knapweed, dalmatian toadflax and houndstonge.

Download the June 2012 Monthly Weed Post from Montana State University.

Visit the MWCA Biological Weed Control page for more information.  Contact your local weed coordinator for help getting biocontrol agents in your area.

Mapping the Weeds on the Madison River

Wednesday, August 4th, 2010


Bozeman Daily Chronicle recently featured an article about mapping weeds on the Madison River.

ON THE MADISON RIVER — Floating along the shoreline in his drift boat, Travis Morris pointed to a 25-yard stretch of purple flowers.

“That’s a huge infestation right there,” Morris said.

The flowers, better known as Canada thistle, look pretty. But the plant is actually a weed that takes over any ground it comes in contact with and chokes out native plants. And without those native plants, the riverbanks erode, water quality deteriorates and fish can’t reproduce.

“This river is in a spot where the weeds are here, but they can still be controlled,” said Matt Wilhelm, education director for the Livingston-based Center for Aquatic Nuisance Species.

Wilhelm and Morris, president of the Bozeman chapter of Trout Unlimited, floated the Madison on Tuesday looking for noxious weeds and recording their location with GPS coordinates.

Read the complete article on the Bozeman Chronicle website.

Weed of the Week – Houndstongue

Thursday, July 22nd, 2010



Houndstongue was introduced into the U.S. in the 1900’s from Eurasia as a cereal contaminant.  It is also known as sheep’s lice, dog’s bur, beggar’s lice, woolmat, and glovewort.  The seed of houndstongue has been said to be the inspiration for Velcro.


In Montana, houndstongue infests an estimated 36,000 acres.  Where it is established it will displaces native vegetation and cause problems on pasturelands. The taproot of houndstongue grows deep into the soil and is very efficient at capturing soil nutrients and water reducing what is available for beneficial native grasses and forbs.

It has an uncanny ability to disperse its seeds. The seeds of houndstongue are covered with Velcro-like barbs that attach to clothing, hair, fur, and feathers.  They can be transported long distances into new areas by animals, people, vehicles, etc.  Each plant can produce up to 2000 seeds that can remain viable on the parent plant for 2-3 years.

Houndstongue is not generally palatable to grazing animals but on occasion when they are in a confined area with nothing else to eat they will graze on it.  This can be a problem because houndtongue contains poisonous chemicals that in high doses can kill an animal.  The chemical found in houndstongue is pyrroli-zidine alkaloids, which will cause liver damage in horses and cattle but not in sheep.


Houndstongue is a member of the Boraginaceae (Borage) family.  It is a biennial, meaning that its lifecycle is completed in two years.  The first year a rosette will emerge and the second year flowering stocks will grow up to 4 feet tall.  The rosette and flowering stock leaves are oblong and are covered in soft white hairs.  The deep vienation on the leaves is said to resemble a hound’s tongue, which lead to its common name.  The flowers range from red to a deep burgundy.  Each flower produces a seed cluster containing 3-4 teardrop-shaped fruits or nutlets.  It begins flowering in mid-June.

What can you do?

The most important management tool for houndstoungue is prevention. It is important to not let this weed spread and establish in new areas. You can help stop the spread of this weed by: containing infestations, limiting weed seed dispersal, identifying and eradicating new infestations, minimizing soil disturbance, planting competitive grasses, and properly grazing infested areas.

Hand-pulling this weed is beneficial, as long as at least 2 inches of the root crown is removed.  After removing houndstongue bag or burn the weed in order not to spread the seeds. An effective biological control has not yet been release in Montana. There are also herbicides that work well on houndstongue.  For more information on houndstongue or any other weed, call your local county weed district.

Visit the MWCA Weed ID pages for additional information and pictures of Houndstongue.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.