There are aliens among us. They didn’t come from outer space. Instead, they invaded our country from their native lands around the world. Some hitchhiked in bales of hay or on unsuspecting travelers. Others were brought here deliberately, perhaps for their beauty or stalwart endurance in the face of adversity.

Once here, they took advantage of our hospitality and spread far beyond their original destination. These invaders are plants: grasses, flowers, even trees that are taking over our country. It’s time we fight back.

When aggressive plants arrive in a new environment, they upset the delicate ecological balance that sustains birds and other wildlife. We call them “noxious weeds” because they tend to take over the landscape, are difficult to control, and out-compete more useful natives. They are frequently useless as wildlife forage or shelter, while replacing plants on which wild creatures depend.

Noxious weed lists vary by state, as not all plants are invasive everywhere in the country. If your state lists a plant, you are required by law to get rid of it. That may not be so easy. These plants are considered noxious for a reason. In most cases, success involves a combination of hand-weeding, “frustration” (in which you remove all top growth as soon as it appears, until the roots run out of food and give up), biological, and chemical controls.

In Colorado, the state maintains three noxious weed lists. Some invaders are so well distributed that control is hopeless. The best we can do is try to keep them at bay, preventing any new infestations. Bindweed (left) falls into this category, and is listed on list “C.” Other aliens are relative newcomers, and are not yet established over wide areas. Much effort is focused on keeping these weeds from becoming permanent residents. These are “A” listers. The “B” list is in the middle—control would be nice, but it’s probably too late.

Some species on Colorado’s noxious weed “A” list that are found in here in El Paso County include Purple Loosestrife, Orange Hawkweed (right), and Myrtle and Cypress spurges. It is critical that landowners, and even urban homeowners, learn to recognize these weeds and kill them before they can go to seed. Not only is it good for the environment, it’s the law!

More information on identification and control of noxious weeds is available online at the Colorado Department of Agriculture website.