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

Weed Articles

Watch Out for Phragmites – MSU Publication

Saturday, March 26th, 2016


Montanans have a new plant on the state noxious weed list to watch out for. An exotic subspecies of phragmites (Phragmites australis ssp. australis), a large-statured perennial grass, was confirmed in Hill and Blaine Counties in 2014 and was listed as a state noxious weed in 2015.

Read more in the Watch Out for Phragmites publication from MSU.

MSU March Weed Post – Rush Skeletonweed

Tuesday, March 15th, 2016


Rush skeletonweed is a high priority species for Montana due to its limited presence here and our close proximity to large infestations in Idaho. Furthermore, rush skeletonweed could have devastating impacts on agriculture in Montana if it becomes well-established. Management priorities for rush skeletonweed include monitoring, early detection, and treatment of newly invading plants. Hand-pulling is an option for small infestations, but this requires control 2-3 times per year for more than five years.

Download and read the complete weed post: MSU March Weed Post – Rush Skeletonweed

MSU February Weed Post – Tall buttercup seedling growth along a moisture gradient

Wednesday, February 10th, 2016



… Tall buttercup can displace pasture grasses and clovers and is cause for concern due to its toxicity to livestock, especially cattle. In Montana it has invaded over 20,000 acres and is a Priority 2A noxious weed. Irrigation may create conditions conducive to tall buttercup growth and survival, but the amount of moisture required for optimal seedling emergence and growth has not been explored. Understanding the importance of soil moisture on seedling recruitment can inform effective management strategies.

We conducted a greenhouse study to assess seedling emergence and growth along a gradient of soil moisture. We collected seed from tall buttercup growing in flood and sub-irrigated hayfields in southwestern Montana, planted them in soil in half gallon pots, and subjected them to three soil moisture treatments including 25, 50, and 100 percent field capacity (field capacity = amount of water held in soil after excess water has drained away, usually 24 hours after a wetting event). After 65 days, tall buttercup seedlings in each pot were counted and measured.

Tall buttercup seedling emergence, height, number of leaves, and biomass were all affected by soil moisture…


Download and read the complete weed post: MSU February Weed Post – Tall buttercup seedling growth along a moisture gradient.

Phragmites ID

Saturday, October 31st, 2015


Find out all about these invasive species by clicking HERE.

MSU Annual Report: MNWTF June 2015

Friday, September 18th, 2015


To view the annual report please CLICK HERE.

MSU July Weed Post – Weed Spread & Climate Change

Monday, July 14th, 2014


This month’s post comes to us from Dr. Lisa Rew, Associate Professor in the Department of Land Resources and Environmental Sciences at MSU, and highlights some of her recent work looking at weed spread along elevation gradients and how this may help us better predict patterns of invasion within the context of a changing climate. If you have any questions regarding her research, please contact Lisa directly at

Excerpt from this month’s weed post:

Whether we like it or not, our climate is changing: generally Montana is getting warmer and patterns of precipitation (amount, form -snow or rain, timing) have changed in various ways across the state.  In addition, the human population continues to grow in many parts of Montana, and this has increased the frequency and intensity of road and trail use. Understanding how weeds respond to such changes and where new populations are likely to occur is helpful for planning weed management at the broader scale. Dalmatian toadflax, originally from Eurasia, has been present in southwest Montana since the early to mid-1900s and occurs in a range of areas including our more mountainous areas. Weeds respond to disturbance and are more abundant on bareground than in healthy growing vegetation, which is why they are abundant along roadsides. So what is stopping the spread of this and other species to higher elevations and away from roads and trails? Are seeds not getting there? Is the climate so inclement that seeds arriving at higher elevations cannot germinate or establish? Or, does the intact high-elevation vegetation stop the invasion?

Finish reading the July 2014 MSU Weed Post.

MSU April Weed Post – Grass Identification

Tuesday, April 15th, 2014


Here is an excerpt:

Grasses are a ubiquitous feature of the western landscape.  In fact, over two thirds of Montana is dominated by grasses, and over 236 grass species have been documented in Montana.   World-wide there are about 10,000 grass species. Differentiating one species of grass from another is difficult because they tend to all look very similar.  However, grass identification is critical for assessing when and where certain weed management tools should be applied. For example, some grass species are more susceptible to broad-leaf herbicide injury than others.  Accurate identification of the grasses on a site is essential to help select an herbicide that will be most effective on the weed while being least harmful to remnant, desirable grasses.

Download and read the complete weed post: April 2014 MSU Weed Post – Grass Identification

MSU October Weed Post – Weed ID

Wednesday, October 30th, 2013


Plant Identification—To Know You Is To Love You
The ability to identify a plant is important for several reasons. From a vegetation management perspective, it is important to know a plant’s identity so you can determine if it is a weed and the level of risk it poses to desired vegetation. Identification is especially important for early detection of new weeds that have never been documented in an area before and can be targeted for eradication. Plant identification is also important to determine if a plant is toxic, especially for people who raise livestock or harvest edible plants from the wild. Knowing what plant you or your animals are about to eat can become a matter of life or death. Finally, being able to identify a plant is just plain fun and a great way to impress your friends and family. Most people that spend a lot of time dealing with plants, including weedy plants, find that plant identification becomes something they grow to love and take great pride in being able to do.

Read the complete October 2013 MSU Weed Post

MSU September Weed Post – Seed Dispersal by Vehicles and Hikers

Wednesday, October 30th, 2013


The September Weed Post which discusses weed seed dispersal by vehicles and hikers.  You may find this post especially interesting/useful as you get ready for hunting season, whether that be through your own hunting adventures or interacting with hunters on public and private land.

Excerpt from the September Weed Post.

Going my way? Weed Seeds as Hitchhikers

Weeds are often found along roads and trails because such areas are disturbance-prone and weed seeds are dispersed by humans traveling along such routes.  A growing body of research suggests weed seeds are catching a free ride as we drive our regular routes and hike our favorite trails.

A series of studies conducted at Montana State University measured the number of seeds picked up by vehicles and the distance seeds traveled on vehicles before they fell off.  Different types of vehicles, road surfaces, and moisture conditions were studied to determine how they affected seed dispersal.  One study revealed that ATVs collected a large number of seeds when driven on- or off-trail, and more seeds were collected in the fall than in the spring.  The highest number of seeds, about 5,500 seeds/mile, was collected from ATVs driven off-trail in the fall.  Even when driven on-trail, ATVS collected about 400 seeds/mile in the fall.  A second study determined   that many more seeds were collected by vehicles driven under wet conditions than under dry conditions. The third study found that >90% of seeds stayed attached to a vehicle for at least 160 miles under dry conditions, allowing for long distance transport of seeds.  Read the complete post September 2013 Weed Post

Another good reference on seeds traveling by vehicles can be found in  the MSU Extension MontGuide “Weed Seed Dispersal by Vehicles” (

MSU August Weed Post – annual grass, Ventenata dubia

Wednesday, October 30th, 2013


The August Weed Post features the annual grass Ventenata dubia.  This summer we have received inquiries about this plant at the rangeland weed lab and Schutter Diagnostic Lab, so I thought it would be a good candidate for this month’s post.  Don’t hesitate to contact me if you have questions/comments about this plant.

It is not on the Montana Noxious Weed List.

Read the complete Augus 2013 MSU Weed Post with pictures and maps.