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The Weekly News Source for Wyoming's Ranchers, Farmers and AgriBusiness Community

Invasive species lurking under the snow

by Wyoming Livestock Roundup

Wyoming winter has already shown its proclivity towards deep snow this year. It may be easy to only look at the snowdrifts, but it is vital to remind ourselves to think about what is hiding beneath.

Invasive plant species are a yearlong problem needing attention even on the dreariest of winter days. 

Winter is an opportune time to have a conversation with a local Extension educator or Weed and Pest office about the invasive species on a person’s property and how to treat them. Planning ahead can help improve grazing strategies for weed management and ensure there are herbicides on hand when it’s time to start treating. 

Invasive winter annual grasses, species emerging in the fall and over winter, before continuing to grow, have a very small window where treatment is successful in the spring. It is important to have a management plan in place so when those species do begin growing producers are prepared to treat when the likelihood of success is highest. 

Many perennial species such as leafy spurge, Canada thistle and knapweeds have more effective control when treatment occurs while root nutrient reserves are depleted by early spring growth. 

Prescribed fires

Winter and early spring may also be a great time to use prescribed fires to manage invasive species. Prescribed fires may be safer during this time due to more predictable wind, lower fuel moisture and when snow banks can be used as fire breaks. 

Prescribed fires can have varying effects on vegetation communities, so be sure to do thorough research and preparation before burning. A great place to start is with Derek Scasta’s publication, “Wildland Fire in Wyoming: Patterns, Influences and Effects.”

Early detection

Seed dispersal is a possible way for invasive species to move around, even in the winter. As humans, equipment and pets move through the snow, seeds may be picked up and moved around. With more of the standing grasses and leaves being pushed down by snow, it is easier for seedpods and burs from standing weeds to catch onto clothing and fur. 

It is important to continue following the PlayCleanGo initiative even in snow. Be sure to stay on trails or roads, clean off boots and equipment and check pet hair and paws for seeds.

Also, keep in mind  seeds of invasive species can be introduced and spread through hay. Prevention is the best management practice with invasive species, so try to purchase certified weed-free hay or hay that has gone through weed control. 

Between drought and rising prices, many producers were forced to purchase hay from new locations which may have different weeds. It is important to search through hay and identify possible new invaders.

Keeping track of where producers feed can also help to prioritize locations to scout for weeds in the following seasons. Early detection and control of small populations of invasive species can save time, money and stress. 

Winter can be an opportune time to learn more about invasive species. When the weather pushes landowners inside, they should use this time to review identification, management options, new treatments or to make management plans for springtime. 

Check out University of Wyoming Extension Publications for a wide variety of educational materials. 

Additionally, the weed management guides titled “Weeds of the West” and “Nebraska Extension Guide to Weed Management” can help identify weeds and determine a management plan for them. 

Invasive species can dramatically change our rangelands. It is important to properly manage them and to remember every season counts when it comes to controlling invasive species. 

Jaycie Nicole Arndt is a University of Wyoming invasive grasses Extension educator. She can be reached at 

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