Are we ready to Coexist? Take Action – Invasives Weeds Flowering Now!

Are we ready to Coexist?  Take Action – Invasives Weeds Flowering Now!

After all the spring rain, the summer wildflowers sure are popping!  Currently, the tint of blue flax is coloring the High School Butte Trail and pink geranium peeks up at you on the wooded Snow King trails.

Unfortunately, many of the blooms right now are invasive weeds, which come in all colors and types.  Invasives plants are not native to this area, can outcompete natives, and cause harm to ecosystems.  The good thing about seeing invasive flowers is that it means the plant has yet to make seeds (which will come from the fertilized flowers).  If we can cut, pull, or chemically treat the weeds before they make seeds, we might be able to prevent them from reproducing next year.  And many invasives are annual (living for one year) or biennial (living for two years) plants, so if we can stop their seeds, we can eliminate them.

Caring for the area we call home by removing invasives is the least we can do to promote human-wildlife coexistence. Below is data on areas affected by and treated for invasive species over the last decade in Teton County, collected by Teton County Weed and Pest, and published in the Jackson Hole Alliance’s First Ever Human Wildlife Coexistence Report.   There is a clear inverse relationship between the area treated and the area affected – showing that the treatment work has been effective.  But anyone who has tried to control invasives knows that the work is never done, and one needs to be vigilant to identify and treat invasives early before they get out of control.

For the second year, Teton County Weed and Pest has sponsored the Invasive Cost-Share Program for landowners in Teton County. This program allows landowners in the county to be reimbursed for their time and expense in treating invasive weeds on their property.  All you need to do is register by July 31st, 2023 here.  Reimbursements are calculated at a base rate of $100 per parcel and an additional $25 per acre, up to a maximum of $2,000.  Teton County weed and pest also offers resident consultation and land management planning assistance to anyone residing in Teton County – call their office at 307-733-8419 to make an appointment.

To help you get started, below is a quick guide to five of the most common invasive weeds in the county: Remember, getting to them before their flowers turn into seeds is how we defeat many of these incredibly resilient weeds. Wear gloves, protective clothing, and a sun hat – this is not for the faint of heart – coexistence requires work!

Opinions vary concerning the use of herbicides, as some people choose not to use chemicals on the land.  While chemical herbicides are a valuable tool for large invasive outbreaks, they can affect non-target species and leave residual chemicals in the environment.  Hand pulling alone can be highly effective, especially when employed at the right time, on the target species, and before the outbreak becomes unmanageable by hand.


Photo from: https://www.stgeorgeutah.com/news/archive/2021/03/29/ajt-considering-both-cost-and-efficacy-cheatgrass-removal-and-rangeland-restoration-remain-sticky-issues/ 

     A relative newcomer to the valley, cheatgrass has the potential to spread quickly, and is favored with warmer climate and after wildfire or other disturbances that create bare soil.  It also dries out early and burns readily, increasing fire hazard.  This plant is an annual, so if we can pull or cut the plant before it seeds, we can stop its reproduction for future years. 

    A newer herbicide, Rejuvra, has been effective at controlling cheatgrass (it stops all seeds from germinating for up to 3 years). Teton County Weed and Pest will begin aerial spraying with a helicopter for cheatgrass in late July and August. If you have large infestations of cheatgrass, Rejuvra might be the right tool for you – available at Teton County Weed and Pest.  


Photos: https://www.tcweed.org/blog/weeds-of-the-month-houndstongue-black-henbane

Houndstongue’s deep magenta flowers are small, 5-petaled, and grow along wiry stalks. These flowers produce 4 prickly burs that stick like Velcro to your clothes and transport the seeds for next year’s crop of houndstoungue. This plant has a biennial growth habit, meaning it has a two-year life cycle – the first year it just grows leaves, the second year it grows larger, flowers, makes seeds, and dies.  Wear gloves, it is toxic to animals and people when ingested.

Black Henbane:

Photos: https://www.tcweed.org/blog/weed-of-the-month-houndstongue-black-henbane

This member of the nightshade family plant is unmistakable. Its leaves look like a head of cabbage and its foul-smelling flowers look like they might appeal to dung beetles or houseflies as pollinators. Once pollinated, its flowers produce pineapple-shaped fruits packed with small black seeds. This plant has a biennial growth habit, meaning it has a two-year life cycle – the first year it just grows leaves, the second year it grows flowers, makes seeds, and dies. Wear gloves, it is toxic to animals and people when ingested.

Spotted Knapweed:

Photo: https://beef.unl.edu/beefwatch/2021/range-and-pasture-weed-week-%E2%80%93-knapweed-spotted-and-diffuse

The flower head of spotted knapweed is shaped like a miniature vase that is approximately 0.25 inches wide by 0.5 inches long and remains on the plant after maturity.

The flowers spread out from the top of the flower head with purple to pink or rarely white petals. The flower heads are wrapped in yellow-green to brown bracts that are tipped with a black comb like fringe that gives the flower head a “spotted” appearance.  This plant has a biennial growth habit, meaning it has a two-year life cycle – the first year it just grows leaves, the second year it grows flowers, makes seeds, and then dies.   The best way to control knapweed is to detect it early and eliminate it by hand pulling before it goes to seed.

Oxeye Daisy:

Photo and information: https://www.tcweed.org/blog/weed-of-the-month-oxeye-daisy

Oxeye Daisy is the dainty white flower that blankets open fields in and around Wilson. Though it might be considered pretty, this plant is displacing native plants and causing damage to our ecosystem. 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.  Mature plants have narrow leaves, sparsely distributed along the stem. Once oxeye has flowered and gone to seed, the seeds may be viable for up to 39 years!

To treat oxeye daisy, dig out entire patches, removing all rhizomes – expect to dig at least 6 inches down to get all rhizomes out.  Next, Spray with an herbicide like Opensight, which is available at Teton Count Weed and Pest. Repeat treatments in spring and fall each year until the seedbank is exhausted.


Keeping your property free from invasives is one small step you can take personally to ensure that we properly steward our land here in the Tetons.  Controlling invasives makes more room for native plants, on which our wildlife depend.  Thanks for playing your role in providing for Coexistence!


Phone: (307) 733-9417
685 S. Cache St. PO Box 2728
Jackson, Wyoming 83001