All posts by TCWeed

Weed of the Month: Spotted Knapweed

Spotted knapweed (Centaurea maculosa) is blooming and suddenly seems to be everywhere.  It’s grey-green wiry foliage help it blend into surrounding vegetation until its pink flowers appear. Then suddenly we see the vast extent of its infestation.

Spotted knapweed is in the aster family, along with many other noxious weeds including Oxeye Daisy, Scentless Chamomile, and all the thistles. The pink flowers of spotted knapweed are reminiscent of Canada Thistle, but knapweed lacks the spiny leaves of thistles. Spotted knapweed can also be distinguished by the black tips on the bracts that make its involucre appear “spotted”(and give the plant its common name).

For those who are not botanists, the involucre is the whorl of bracts (scale-like structures) surrounding the inflorescence of flowers in the aster family.  

Like many noxious weeds in our area, spotted knapweed is native to Eurasia where the climate is similar enough to the rocky mountain west that it can thrive here. In its homeland, it has many limiting factors that keep it from being invasive. These include competition from other plants and herbivores that like to feed on it. However, such limiting factors are not present in the Greater Yellowstone Ecosystem, which allows the spotted knapweed to reproduce and spread, apparently unimpeded.

This creates a challenge for our native wildlife. Spotted knapweed can provide reasonable nutritional value to ungulates when it is young and green. But once it produces flowers, a chemical in its leaves make it unpalatable. Over the course of a year, the nutritional value of spotted knapweed to grazing ungulates is very poor. The knapweed also has the ability to reduce competition from surrounding vegetation by releasing a chemical from its roots that inhibits germination of other plants. So eventually, spotted knapweed can replace the native grasses and forbs that wildlife rely on with a forage of much lower quality.

Elk eat knapweed unwillingly after it has replaced more nutritionally valuable native grasses
Photo credit: Casper Star Tribune

If you have spotted knapweed in your yard, you may notice that it will eventually replace everything else growing in your yard and make your soil less hospitable to other plants, decreasing your property value.

So what can you do if you find spotted knapweed growing on your property?

  1. You can dig it up if you get the entire root out
  2. You can treat it with an herbicide like Milestone, available at Teton County Weed and Pest.
Spraying spotted knapweed along the Gros Ventre River

If you are not sure that what you have is spotted knapweed, click here and submit a Weed ID service request with an uploaded photo of your weed and we will confirm its identity. You can also bring a sample to our office.

PlayCleanGo Partner: Scenic Safaris & Mad River Trips

Teton County Weed and Pest District wants to applaud the efforts of our PlayCleanGo partners in the valley. PlayCleanGo: Stop Invasive Species In Your Tracks® is a nationwide outreach campaign made up of passionate outdoor enthusiasts (individuals and businesses) working tirelessly to protect our natural resources.

We are proud to feature Scenic Safaris & Mad River Trips for our first PCG partnership and the efforts they take to practice these principles in their wildlife adventure tours and rafting trips in the summer.

1. Why did you decide to become a PlayCleanGo partner? 
From a company’s perspective though keeping a wrap on potential invasive species is important to us. If we do not manage the potential then the problem will manage itself which is the most undesirable for everyone from company, employee, local enthusiasts and our guests. We are just doing a component with keeping our machines cleaned thoroughly after each use.

2. How do you advocate for PlayCleanGo practices through your company? 
We could do a better job talking about it to our employees for sure. Our belief is in our daily practice of operations which allows us to know its being done very thoroughly. 

3. What invasive species do people need to be especially aware of in Jackson? 
Unfortunately we have noxious weeds as well as the aquatic invasive in the valley. We have more potential threats in the region (ie the zebra mussel.)  We focus on both terrestrial and aquatic inspections and cleaning, for noxious weeds we wash all overland vehicles after each use, especially when traveling off the tarmac.  Our rafting operation gets inspected regularly by our staff as well as the AIS staff where we register our boats as every other boat owner to comply with those regulations.

4. What do you think is the best way to spread awareness to friends and family members about the detriment invasive species pose to society?
My opinion is that they must be able to see visually what the problem looks like and have the compassion to feel that the effort is warranted to where they themselves want to take action. I feel like this is a tall task. 

5. Do you share PlayCleanGo practices with visitors to Jackson and GTNP? If yes, how do you do that? 
Something that we could do a better job with as a company. We do have educated staff that know of these issues in our community and even deal with them at their homes. We do not have our staff do a presentation on this with clients at the moment, but I know that it is a topic of conversation with customers because it was a topic discussed often when I guided day to day. 

Considering becoming a PlayCleanGo Partner? 

What if every outdoor enthusiast were provided with the tools to Stop Invasive Species in their Tracks? Could we stop them? We think so. We have 550+ partner organizations already, representing thousands of individuals who believe we can do it too.

Join forces with like-minded individuals, organizations, and businesses across North America. Become a PlayCleanGo partner now!

Doing Your Part Giveaway

Teton County Weed & Pest District is excited to be holding the “Doing Your Part Giveaway” to promote PlayCleanGo practices throughout Teton County this summer season.

Please share your photos/videos of you giving invasives the brush off whether you’re biking, hiking, horseback riding, ATV adventuring and more. Follow us on Instagram and use the hashtag #doingmypart #PlayCleanGo and mention us to enter.

You could win one of the following:

PlayCleanGo boot brush

PlayCleanGo reusable tote bag

PlayCleanGo water bottle


1. Following us on Facebook or Instagram.
2. Share a photo/video and mention us and tag #doingmypart and #PlayCleanGo

Each method is a new entry into the giveaway. 
Winners will be announced mid-August.

What is PlayCleanGo?

This is the initiative to stop invasive species in their tracks. You can help participate by REMOVING plants, animals, & mud from boots, gear, pets & vehicles, CLEANING your gear before entering & leaving a recreation site, STAYING on designated roads & trails, and USING CERTIFIED or local firewood & hay.

Partially funded by the USDA Forest Service, the Minnesota Department of Natural Resources launched the outreach campaign PlayCleanGo: Stop Invasives Species in your Tracks in 2012. The campaign has since expanded to include partner organizations across North America. The campaign has expanded since in large part due to the work of the North American Invasive Species Management Association (NAIMA) who adopted PlayCleanGo in 2015. The campaign goal is to protect valuable natural resources and encourage folks to enjoy the outdoors. Community based social marketing has helped build brand recognition and the objective is to slow (and where possible stop) the spread of invasive species by changing public and worker behaviors at risk of spreading harmful pests living on land or in water. PlayCleanGo promotes awareness, understanding, and cooperation by providing a clear call to action to be informed, attentive, and accountable for stopping the spread of all invasive species.

20th Annual Gros Ventre River Spray Days 2019

Join the Jackson Hole Weed Management Association (JHWMA) for Gros Ventre River Spray Days July 16 – 18, 2019.

Partners in the JHWMA will team up to treat spotted knapweed, houndstongue, and Dalmatian toadflax as well as other invasive plants, which compete with native vegetation and adversely impact wildlife habitat and ecosystem function. This multi-year project has been taking place for over 15 years.  The project area for this event is the Gros Ventre River corridor encompassing the National Elk Refuge, Grand Teton National Park and other public and private lands to the confluence of the Snake River. This project is being organized by Grand Teton National Park, Bridger-Teton National Forest and Teton County Weed & Pest District (TCWP).

JHWMA - Backcountry Horseback Spraying - Man on Horseback in front of Tetons image

The first indication of knapweed on the Gros Ventre River is briefly discussed in minutes from a Weed and Pest District Board meeting in 1974, though the exact location is not mentioned.  In 1999, JHWMA partners decided it was important to begin recording the presence of noxious weeds throughout Teton County. The Gros Ventre River from the Goosewing Ranch area to the confluence with the Snake River was surveyed as part of this effort. At that time, spotted knapweed was only located as far upstream as the Forest/Park boundary. No other infestations were identified upstream (east) of this location. This prompted the beginning of what is now known as the JHWMA’s Annual Gros Ventre River Spray Days project.

In 2000, crews from Grand Teton National Park, the Bridger Teton National Forest, Teton County Weed and Pest, and the National Elk Refuge began targeting spotted knapweed along the river corridor in the hopes of reducing and containing the infestation and keeping the infestation from spreading further east into the Gros Ventre area.  Despite these efforts, in 2001 spotted knapweed was found between the Forest/Park boundary and Lower Slide Like on the Gros Ventre Road. Then in 2008, it was found in the campground at Lower Slide Lake. This indicates that in addition to traveling downstream, knapweed is also traveling up the road with humans (vehicles, horses, snowmobiles, UTV’s, etc).  This movement highlights the importance of public awareness of how we can prevent the spread of invasive species to our favorite recreation areas by following PlayCleanGo ( principles.

Gros Ventre River Spray Days continues to be integral to the protection of wildlife habitat in Grand Teton National Park and the National Elk Refuge. The JHWMA Spray Days event is unique in that it pulls together groups from across western Wyoming.  “The goal is to contain and reduce the spotted knapweed infestation that is thought to have started on the Gros Ventre River in the 1970’s”, stated Erika Edmiston, Supervisor at TCWP. “Without this amazing group coming together for this team effort, we would be losing critical wildlife habitat to these invaders”. Unfortunately, the spotted knapweed infestation is so extensive in this corridor that it will never be eradicated. However, with careful planning and targeted treatments, JHWMA partners are containing and reducing the infestation. Annually, crews treat roughly 50-100 acres of invasive species in this 1,200+ acre project area, thanks to grant funding and dedicated funding from agencies.

“A lot of really great people have come together over the years to make progress on some awfully bad plants which negatively transform ecosystem function in wildlife habitat and an important elk migration area.” said Travis Ziehl, Jackson Hole Property Services.

Agencies, organizations, and businesses that have assisted with the project over the years include but are not limited to:

Fremont, Lincoln, Natrona, Park, and Teton County Weed and Pest Districts in Wyoming, Bonneville and Teton County Weed Districts in Idaho, Jackson Hole Fire/EMS, Boreal Property Management, Jackson Hole Property Services, Intermountain Aquatics, the Bridger-Teton, Custer Galatian, and Shoshone National Forests, the National Elk Refuge, Yellowstone and Grand Teton National Parks as well as the National Park Service – Northern Rockies Exotic Plant Management Team.  The Bureau of Land Management, Wyoming Department of State Lands, Jackson Hole Land Trust, Hanna Outfitting, Gros Ventre River Ranch, Jackson Hole Golf and Tennis, Teton Conservation District and the Rocky Mountain Elk Foundation.

The JHWMA was formed in 1998 to establish common long and short-term management policies, goals, and objectives necessary for cooperatively managing and funding noxious weed activities across all jurisdictional boundaries. 

We would like to thank the Teton Conservation District (TCD) and the JHWMA for their contributions in making this event a success. To learn more about the JHWMA  please visit

New Teton County Weed & Pest District’s Logo

Teton County Weed & Pest District has had their logo for 5 years now and they were looking to a reboot their branding approach. Keeping their mark recognizable was important to them and maintaining the acronym TCWP was important. They were open to a new modern approach. Since the public were starting to relate TCWP’s brand it was imperative to subtle evolve the brand rather than making a radical change.

A little TCWP History

TCWP was established by the Wyoming State Legislature in 1973, consists of a locally appointed government board charged with implementing and pursuing an effective program for the control of designated and declared weeds and pests.

Read more history on TCWP .

Old TCWP logo

The old logo’s TCWP letters were getting lost among the mountains and the general consensus was for the new logo to be easy to recognize from near or far.

The earthy greens were chosen to evoke TCWP’s stewardship of our cherished lands of Teton County. The role of TCWP could be characterized as guardians of Wyoming’s rich ecosystem and this logo was set to evoke a badge of that responsibility.

New TCWP logo – light green
New TCWP – one-color (dark green)
New TCWP logo – dark green
New TCWP – one-color (light green)

Earthy greens and a warm grey

Nevis Bold
Sanchez Regular

Logo design by Gliffen Designs

Weed of the Month: Oxeye Daisy

Oxeye daisy (Leucanthium vulgare) is the dainty white flower that you see blanketing open fields in and around Wilson, giving the impression of snow in summer. 

Although a field of daisies may seem preferable to a field of spiny thistles, or bur-covered houndstongue plants, the impacts on native plant communities and the wildlife that depend on them are the same. 

The 50-ish invasive plants we are mandated to control in Teton County are so named because they don’t just colonize disturbed areas, they INVADE established native plant communities and displace native plants. The characteristics that allow oxeye daisy to invade include the ability to spread through underground rhizomes, a lack of palatability to wildlife and cattle, the ability to tolerate a wide range of soil conditions, and freedom from the predators and pathogens found in its native Eurasia.

Oxeye daisy belongs to a cohort of invasive plants that are often considered too pretty to be a problem. Along with  Dame’s Rocket, Dalmatian toadflax, and others, oxeye daisy is at risk of not being treated due to its perceived beauty and the fact that it is so easy to cultivate. 

Dames Rocket and Dalmatian toadflax are invasive plants that people hesitate to eradicate because of they are pretty AND very easy to cultivate 

But be warned, once oxeye has flowered and gone to seed on your property, you will have daisies coming up for many years to come. Once you start treating them, it will take at least 6 additional years to exhaust the seedbank. One study found oxeye daisy seeds to be viable in the seedbank for 39 years! So the sooner you begin treatment, the better.

Oxeye Daisy Treatment options include:

  1. Dig out entire patches, removing all rhizomes – expect to dig at least 6 inches down to get all rhizomes out.
  2. Spray with an herbicide like Opensight, which is available at TCWP. Repeat treatments in spring and fall each year until the seedbank is exhausted.

Finally, if you really want daisies in your yard, consider planting Shasta daisy. Like oxeye daisy, it is easy to grow, but it is not invasive. Here are some photos to help you differentiate these two daisies:

Can you tell which is which?

Mosquito Season Yet Again.. 2019

With the onset of the summer and its warmer days and longer nights comes mosquitoes. It may seem that their bite may just be a mere annoyance but it can be much more severe than that. Mosquito bites can spread diseases like West Nile Virus and Zika. Mosquito-borne diseases do not only affect humans – they also kill countless birds, reptiles, animals and endangered species each year. Joseph Conlon, AMCA Technical Advisor stated on the subject, “We are continually importing the diseases they carry. We must be prepared to prevent their spread throughout our public health landscape – and this requires safe, effective, sustained mosquito control and awareness in our community.”

National Mosquito Control Awareness Week – June 23-29

June 23 – 29 is “National Mosquito Control Awareness Week” by the American Mosquito Control Association (AMCA) to help spread public awareness about the importance of mosquito management practices. As part of “National Mosquito Control Awareness Week”, Teton County Weed & Pest District would like to share their top abatement priorities for mosquitoes, which are as follows:

  • Vector control for West Nile virus prevention
  • Bio-rational approach to vector control – utilize larval surveillance and treatment as primary means of control to reduce off target impacts. BTI larval treatment is a selective pesticide.
  • Survey and trap adult mosquitoes to determine need for Ultra Low Volume (ULV) fogging.
  • Larval control is the most efficient way to reduce mosquito abundance
  • Encourage a reduction in man-made sources of mosquito breeding habitat

Though one of the major banes of summer that seem inevitable, there are still measures you can take to ensure you and your loved ones have an enjoyable season. What are a few things that landowners and the public can do? You can help identify and report mosquito habitat, help us fill in the permission gaps for surveillance and treatment, dispose of any unused tires on your lot, drill holes in the bottom of recycling containers, clear roof gutters of debris, clean pet water dishes regularly, check and empty children’s toys, repair leaky outdoor fauces, and change the water in bird baths at least once a week, encouraging neighbors to take part in the same preventative measures, and make sure to always practice the 5 D’s of mosquito prevention below:

5 D’s of Mosquito Prevention

  1. DUMP – By periodically dumping standing water you can prevent mosquitoes from growing into adults that feed on you
  2. DRAIN – Regularly draining standing water sources like pet water dishes, water troughs and kiddie pools. Reduce mosquito breeding habitat by not allowing water to stand for long periods of time.
  3. DRESS – Dressing for outdoor activities by wearing long pants and long sleeve shirts made of lighter material like linen are ideal for hot summer months. Consider hats with mosquito netting.
  4. DEET – Use an insect repellant that lists DEET or alternatively lemon eucalyptus oil to prevent mosquito bites. DEET is proven to be the most effective mosquito repellant.
  5. DUSK/DAWN – Mosquitoes are most active during the early morning and evening hours. Try to stay indoors during these time periods. If that’s not possible be sure to dress to prevent bites and use a DEET repellant.

With a few pre-meditated measures, you can help ensure an enjoyable summer, free from the worries and annoyances of mosquitoes around every corner. Take the time to protect you, your family, and community from the grievances of mosquito pests this summer season. Follow Teton County Weed and Pest’s Facebook and Instagram accounts to learn more preventative measures you can take to control mosquitoes throughout the summer season.

Weed of the Month: Houndstongue & Black Henbane

Some of the first noxious weeds that bloom every spring are Black Henbane and Houndstongue. Both are easy to recognize once they flower.

The houndstongue produces deep magenta-colored, five-petaled flowers along wiry stalks. Each flower will become a cluster of four burs that carry the plant’s seeds and will stick to passers-by like Velcro.

Black Henbane has foul-smelling whitish flowers with purple centers. Once pollinated, its flowers produce pineapple-shaped fruits packed with small black seeds.

Both of these plants are biennial- meaning they live for two years – and if you are seeing them in flower, this is the last year of their life. Before they die, they have one wish – to reproduce! They have until fall to produce as many seeds as they can to assure that their progency will live on for many generations. If they get their wish, we can expect a large crop of these weeds to pop up each spring for many years to come.

But since they are biennial, we have some choice in the matter. Here are our options:

  1. Find flowering adults and dig them out! They have a fairly deep taproot, but if you can dig the plant out below the root crown, it will not come back. Since both of these plants have toxins in their leaves, be sure to use gloves when pulling them out.
  2. Spray flowering adults with herbicide! Visit us at TCWP to find the right herbicide for your situation. Note that once biennial plants have gone to seed it doesn’t make sense to spray them because their seeds will still spread and the plant is at the end of its life cycle anyway. If they are in seed, pull them.
  3. Learn to recognize the plants in their first year – when they are NOT flowering – and spray them with herbicide. This is the most efficient way to control these biennial weeds. See below for identification tips.

Houndstongue looks like a cluster of long, hairy, tongue-shaped leaves with pointy tips. It can be confused with native arrowleaf balsamroot at this stage, as that plant also produces a simple cluster of leaves in its first year and those leaves are a similar shade of green. But look closely at the bases of the leaves and you will notice that balsamroot has a distinctive spade-shaped base while houndstongue leaves simply taper to a point at their base.

Whether the Houndstongue is in its first or second year, it can be pulled out by hand if the soil permits. If chopped out below the root crown, it rarely grows back. If the infestation is too large to hand-pull, purchase herbicide at TCWP and use a surfactant to be sure the herbicide permeates the hairy leaves.

Black Henbane resembles a head of cabbage in its first year. But you wouldn’t want to mistake it for an edible plant! All parts of this plant are very poinonous. If you learn to recognize it in its first year, you can chop it out below the root crown or spray it with a TCWP-approved herbicide.

Whichever option you choose, make sure you get rid of these plants before they go to seed and remember to PlayCleanGo so you don’t spread their seeds into uninfested areas.


20th Anniversary JHWMA – Current Teton Conservation District Grant Requests

Below are some of the most notable details and results of Jackson Hole Weed Management Association’s current grant requests with Teton Conservation District.

Backcountry Horseback (2004 – Present)

Over the last five years, 4723 miles of trail and hillsides have been inventoried and treated. An average of 945 miles per season.

Snake River Project (2002- Present)

  • Began in 2002
  • In 2018
    • 63.58 acres
    • 8 new Perennial Pepperweed
    • 1 Saltcedar
    • 778 records of priority species checked yearly
  • In 2019
    • Working Dogs for Conservation

Images represent State & Private Forestry Grant Support received.

Cheatgrass (2011 – Present)

Cheatgrass is invading critical winter big game habitat of southern aspect slopes, state and federally managed elk feedgrounds, migration corridors, and Grand Teton National Park. It is threatening both habitat and wildlife health. Included below are images from our monitoring efforts to measure efficacy. (Images from 2011-2013, 2017)

2018 – Treatment Results

Esplanade (Indaziflam) plots:  Overall Decrease from 23.11% to 6.54%

Plateau (Imazapic) plots:    Overall Decrease from 18.22% to 4.28%

(More monitoring to come in 2019 via partnership with UW Weed Science grad student.)

JHWMA Cheatgrass Mitigation Project -2018 Results image.

2018 – Treatment Results

Esplanade (Indaziflam) plots:  Overall Decrease from 23.11% to 6.54%

Plateau (Imazapic) plots:    Overall Decrease from 18.22% to 4.28%

Caribou-Targhee Assistance (2016-Present)

The focus of this project is to inventory and treat invasive species along trail system leading into the wilderness (Teton Canyon pictured in images below, in addition to, isolated patches of various weed species).


We’ll continually post about our 20th Anniversary with Jackson Hole Weed Management Association with a reflection of what we have achieved in the past twenty years. Stay tuned.

JHWMA - Education Programs Students Marking Weed Area image

20th Anniversary JHWMA – Early Cooperative Efforts

Our team has accomplished a lot in 20 years. Outlined below are some of our early projects and a few community engagement activities our team has participated in. We hope you come to realize how committed we are to eradicating invasive weeds in Teton County and continuing to serve you for many years to come.

Early Cooperative Efforts:

  • Vehicles and Spray Equipment
  • Employee Housing
  • Mapping Equipment and Technology
  • Collection of Bio Control Insects
  • Sharing of Information
  • Training

Education Programs:

  • Local Events
  • Classroom
  • Weed Pulls
  • Trail Days

Gros Ventre River Spray Days

  • 2018 – 19th Year
  • 1st spotted knapweed – 1974
  • Annually crews treat 75-100 acres
  • Over $750,000 spent
  • Over 26 federal, state, local, & private businesses have partnered + dozens of private landowners

We’ll continually post about our 20th Anniversary with Jackson Hole Weed Management Association with a reflection of what we have achieved in the past twenty years. Stay tuned.