JoAnne Skelly: There are many reasons to hate invasive weeds

Shown is yellow starthistle.

Shown is yellow starthistle.

Weeds waste water. Whether the normal, garden-variety dandelion or the noxious perennial pepperweed, weeds take our dwindling water resources away from our desirable native and ornamental plants. For example, the 2.6 million acres in the Central Valley of California of the noxious weed yellow starthistle “consume enough extra water each year to fill 25 percent of Lake Shasta” (California Invasive Plant Council).

Margie Evans, Carson City Weed Coalition coordinator, says that “While we don’t have the acreage of yellow starthistle and other noxious weeds that they do, we have less water to begin with. Invasive plants, particularly those growing along our waterways, suck up available water, increase sediment load on the waterway, clog waterways and reduce habitat and recreation opportunities.”

There are many reasons to hate weeds. They ruin the look of a perfect lawn. They take over flower or vegetable beds. They may be poisonous. They can be fire hazards when they dry out. They may have spines that claw at our animals or us.

There are even more reasons to hate invasive or noxious weeds. Invasive weeds are plants that have been introduced into an environment outside their native range, where they have few or no natural enemies to limit their spread. They can spread rapidly across a landscape. An invasive weed may or may not be classified as a noxious weed.

The term “noxious weed” has a specific legal definition. It is any plant designated by a federal, state or county government to be injurious to public health, agriculture, recreation, wildlife or any public or private property. The Nevada Revised Statutes define “noxious” as any species of plant, which is, or is likely to be, detrimental or destructive and difficult to control or eradicate.

Our common landscape weeds can be controlled, often with hoeing, hand weeding or, as a last resort, chemical herbicides. Invasive or noxious weeds, on the other hand, are almost impossible to control without chemicals and often require years of diligent herbicide application and revegetation efforts.

Weeds seem to be the bane of a gardener’s, homeowner’s or land manager’s existence in a normal-precipitation year. But, in a drought year, our aversion to weeds makes complete sense. The drought is a pressing motivation to stop the spread of invasive plants.

If you have weeds you need identified, send me a picture at or stop by your local Cooperative Extension office with a sample. For more information about weeds, go to

JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at or 775-887-2252.


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