By: Hallie Myhre

Noxious weeds are one of the most consistent and costly management challenges for landowners in Routt County, and drought conditions are bringing that issue to the forefront earlier than usual. With a drier season and limited water expected in many areas, weeds are emerging ahead of schedule and competing more aggressively with native grasses and forage.

In a typical year, timing matters. In a dry year, it becomes critical. Many of the species commonly found across Routt County, such as houndstongue, musk thistle, Canada thistle, leafy spurge, whitetop (hoary cress), and curly dock, are already beginning their growth cycle. These plants spread quickly, reduce forage quality, and, in some cases, can be toxic or harmful to livestock. Once established, they may not be a one-season fix. Most require a consistent, multi-year approach to bring under control. It is far easier to prevent land from becoming overrun with weeds than it is to rehabilitate ground that has already been taken over.

It is also important to understand the difference between noxious weeds and toxic plants. Noxious weeds are designated by the state or county due to their aggressive growth, ability to spread, and impact on agriculture and native ecosystems. These are the species landowners are typically required to manage. Toxic plants, on the other hand, may not always be classified as noxious, but they can pose a direct risk to livestock, pet and human health if ingested. Some plants fall into both categories, but not all do. For Routt County landowners, being able to identify toxic species is just as important as managing noxious weeds, particularly in drought conditions when livestock may graze less selectively and are more likely to consume plants they would normally avoid.

The most effective strategy is to treat early, before plants mature and go to seed. For biennials like houndstongue and musk thistle, spraying before second-year plants bolt is key. Perennials like Canada thistle and leafy spurge often require repeated treatments and close monitoring throughout the growing season. Follow-up spraying later in the spring or early summer is often necessary to catch regrowth or missed plants. In a year like this, those treatment windows are arriving several weeks sooner than normal.

Landowners should also be aware of how water and irrigation influence both weeds and treatment effectiveness. Avoid spraying when water is actively running through irrigated ground, as it can reduce effectiveness and cause unnecessary runoff. Damp soil conditions are generally acceptable, but active irrigation should be paused if possible. With some areas potentially running out of water as early as mid-May this year, grasses may go dormant sooner, which gives weeds an additional advantage if they are not addressed early.

Routt County landowners also have a responsibility to manage noxious weeds under Colorado law. The county identifies and prioritizes certain species for control, and unmanaged infestations can spread to neighboring properties, irrigation corridors, and public lands. Regular monitoring, early identification, and timely treatment are all part of responsible land stewardship in this area.

Beyond spraying, overall land management plays a role in long-term control. Overgrazed or disturbed ground is more susceptible to weed invasion, particularly in areas with shallow soils or shale. Rotating livestock, managing grazing pressure, and allowing desirable grasses to recover can help reduce future infestations. Strategic haying, such as avoiding heavily impacted patches to allow for natural reseeding, can also support recovery over time.

For those needing equipment, the Routt County Conservation District has a 200 gallon sprayer for rent which can be a practical option for treating larger acreage and the Routt County CSU Extension Office has smaller sprayers that can be checked out for managing weeds on a smaller scale. Consistent application and follow-up are more important than scale, but having the right equipment can make a significant difference in efficiency.

This year, more than most, the key is to act early. Walk the property, identify problem areas, and begin treatment before weeds have the opportunity to mature. A proactive approach now can prevent a much larger and more expensive problem in the seasons ahead, while protecting both the productivity and long-term value of the land.

Additional information can be found online on the Routt County Weed Abatement Program.