Overgrazed Placitas faces snakeweed invasion?

We had an interesting talk today with Lucas Vargas, an environmental specialist with the Bureau of Land Management. We mentioned that in areas of Placitas hit hardest by feral horses, we’re seeing a surge of broom snakeweed. In fact, much of the green we’ve been seeing in northern Placitas following the summer rains isn’t our decimated native grasses returning–it’s broom snakeweed. Vargas says this is a common occurrence when an area has been overgrazed.

snakeweed

Broom snakeweed is a marker of overgrazed areas and disturbed soils

Broom snakeweed is a small dome-shaped shrub with bright green foliage and, at the moment, yellow blooms. It’s everywhere you look in Cedar Creek, Indian Flats, the BLM tract, and other horse-ravaged parts of Placitas. And besides the mature blooming plants, you can see countless skinny green shoots snaking upwards from otherwise bare dirt. In fact, as I was standing near one this morning, it suddenly started to wrap around my ankle and….

Okay, kidding. So what’s the problem with this innocent-looking plant? Although a native, it’s as invasive as all heck. It puts out a turpentine-like compound that prevents other plants from growing near it, said Vargas. The more snakeweed about, the harder it is for native grasses and diverse plant communities to return to health after overgrazing. The combination of soils disturbed by livestock and good rains—exactly the combo we had in Placitas this summer— lets snakeweed gain a dominant foothold on the landscape, where it muscles out other vegetation.

Vargas said broom snakeweed can be a tremendous problem on grasslands. He recommends against digging it out or using chemicals to eradicate it. The best approach is to reseed the area with native grasses and hope they squeeze out the snakeweed.

Without active reseeding efforts, this summer’s bumper crop of snakeweed will make it hard for the native grasses to come back. Which means we just might need to call in the Boy Scouts – because right now, there’s an awful lot of land in northern Placitas abloom with this pretty weed.

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Sources: Lucas Vargas, Environmental Protection Specialist, Bureau of Land Management, Cuba Field Office; Ralphs MH, McDaniel KC. Broom snakeweed (Gutierrezia sarothrae): toxicology, ecology, control, and management. Invasive Plant Science and Management. 2011;4:125-132; McDaniel K. Control Perennial Snakeweeds. Guide B-815. Cooperative Extension Service, NM State University, 2003.