Central & Eastern Montana Invasive Species Team

06/15/2026

Great video from MSU extension about identifying Poison Hemlock and Cow Parsnip. Check it out!!

Many plants on county and state noxious w**d lists have native spec...

06/13/2026

Reporting is one of the simplest ways to help protect Montana. Early detection reduces costs and prevents spread. Reports can be made to county w**d districts, MSU Extension, or via tools like iNaturalist and EDDMapS.

Thank you for joining us this week to celebrate Montana Noxious W**d Awareness week!

06/13/2026

Not a noxious w**d in Montana, but cockleburs can have a detrimental impact on our livestock in Montana.

In Montana, cockleburs are recognized as highly competitive, broadleaf annual w**ds that are primarily found in disturbed habitats, fields, pastures, and floodplains.

There are two primary species of cocklebur found in the state, each tracked by the Montana Field Guide:

Rough Cocklebur (Xanthium strumarium): This is a native, stout summer annual with broad, triangular leaves and distinct, two-beaked woody burs covered in hooked prickles. It is widely distributed across Montana, particularly around the Missouri River Breaks and open water courses.

Spiny Cocklebur (Xanthium spinosum): This is a non-native, introduced species that features narrow, lance-shaped leaves, yellowish spines at the leaf nodes, and smaller, beakless burs. It is far less common in the state, with historically few recorded observations centered in valleys like Ravalli County.

Key Concerns:

Livestock Toxicity: The young seedlings and cotyledon leaves of cockleburs are highly toxic to all classes of livestock, particularly swine, cattle, and horses, because they contain carboxyatractyloside. While mature plants are generally unpalatable, accidental ingestion of sprouts in the spring can be fatal ☠️

Agricultural Impact: Cocklebur is a highly aggressive w**d in row crops. It can germinate from deep within the soil (up to six inches), allowing it to easily bypass shallow pre-emergent herbicides and rapidly shade out crops.Bur

Entanglement: The hard, prickly seed capsules easily latch onto animal fur, hide, and clothing. For ranchers, this severely devalues livestock wool and can cause physical injury to the animals.

Management and Control

Mowing and Pulling: Because they are annuals that only reproduce by seed, physically pulling or mowing the plants before they flower and form burs (typically June to November) is highly effective.

Chemical Treatment: Spraying selective post-emergent herbicides like 2,4-D, dicamba, or glyphosate is most effective when the plants are small seedlings (ideally 2 to 6 inches tall) between May and July.

Pasture Management: Keeping pastures healthy and preventing bare ground helps stop cocklebur from establishing, as the w**d requires direct sunlight and does not tolerate heavily shaded environments.

06/12/2026

Meet the Noxious W**d - Leafy Spurge

Don’t be fooled by its pretty yellow flowers, this invasive plant aggressively takes over grasslands, displaces native plants, and its milky latex is toxic to cattle and horses.

It spreads very quickly through seeds and its extensive root system can grow up to 40 ft., making chemical control an important part of longterm management.

For more information: https://agr.mt.gov/Topics/N-P/Noxious-W**ds-Pages/Education/Current-W**ds/Leafy-Spurge

06/11/2026

06/10/2026

Meet the Noxious W**d - Spotted Knapw**ds

Spotted knapw**d is one of the most common invasive w**ds found in Montana. Identified by its thistle-like pink flowers, this invasive species spreads quickly thanks to its prolific seed production (anywhere from 1,000 to 25,000 from a single plant!).

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06/09/2026

Common buckthorn is a strong reminder of why prevention matters. Originally brought to North America as an ornamental shrub, it escaped cultivation and now spreads aggressively in woodlands, riparian areas, and shelterbelts. Once it invades, buckthorn forms dense thickets, shades out native plants, and alters wildlife habitat. Disturbed soil gives it an even greater advantage. The first species to colonize an open patch is often a noxious w**d like buckthorn. That’s why the saying goes: “Cover it up!” Reseeding or mulching disturbed areas
immediately helps prevent reinvasion. Choosing native plants instead of ornamental invasives is one of the simplest and most effective ways Montanans can stop buckthorn and other invaders before they start.

Don’t Plant Common Buckthorn
• Introduced as an ornamental
• Spreads rapidly by seed and root suckers
• Forms dense, impenetrable thickets
• Outcompetes native shrubs and understory plants
• Very difficult and costly to control

Plant These Instead
• Serviceberry (Amelanchier)- Native, wildlife- friendly, and great for hedges
• Chokecherry (Prunus virginiana)- Hardy, attractive, and supports pollinators
• Woods rose (Rosa woodsii)- A tough native shrub that provides habitat and color
• Red-osier dogwood (Cornus sericea)- Excellent for riparian areas and erosion control

06/08/2026

Meet the Noxious W**d: Rush Skeletonw**d

Rush skeletonw**d might sound like something from a Halloween story—but it's very real and very invasive! This w**d has tall, skinny stems with almost no leaves with stiff downward hairs at the base and bright, yellow flowers that spread fast like a dandelion when it does to seed.

Learn more: https://agr.mt.gov/Topics/N-P/Noxious-W**ds-Pages/Education/Current-W**ds/Rush-Skeletonw**d

06/08/2026

Prevention is the most cost-effective w**d management tool. Help us protect the places we love by cleaning your boots, clothes and gear.

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