There are more than 300,000 species of plants in the world. In Colorado we have more than 3000 species. Plants are very important because they are the base of the food chain, that is, everything higher up on the food chain relies on them. Many animals depend on them directly. Herbivores eat parts of the plants and pollinators feed on pollen. Plants are categorized in many ways, including flowering plants, trees, shrubs, herbs, grasses, weeds, and so on. One category you may hear about when talking about local plants are native plants. Native plants are those that have developed in a specific geographic area for a long time. Native flora plays a very specific role in the local ecosystem by providing food and shelter for wildlife, as well as preventing soil erosion. 

On the other hand, there is a group of plants that due to their dispersion, establishment and adaptability are considered nonnative, invasive or harmful. You might even call these plants weeds. These species were introduced intentionally or accidentally and come to compete with native plants for resources such as water, sunlight and soil nutrients. Below, I will tell you about some weeds that we can find around the valley and that you have probably seen before but perhaps did not know that they do not belong to this area.

Canada thistle

Canada thistle (Cirsium arvense), an invasive noxious weed from Europe and Asia, grows 2 to 4 feet tall and has oblong spiny leaves and clusters of 1 to 5 small, tubular flowers  that range in color from white to purple. It spreads by wind-dispersed seeds and its extensive root system, making it difficult to control. This weed is highly invasive, impedes reforestation and restoration, diminishes pasture capacity and desirable forages, and damages wildlife habitat.

Yellow Toadflax

Yellow toadflax (Linaria vulgaris), is an ornamental plant native to the Mediterranean region. With its snapdragon-like yellow flowers and slender leaves, it is an invasive plant with an extensive root system. It spreads through both seeds and root fragments and thrives in various habitats. In mountain environments such as the Rocky Mountains, these plants typically reach a height of one to two feet. Containing toxins that can harm cattle, this adaptable plant is difficult to control due to its resistance to many control methods.

Houndstongue

Houndstongue (Cynoglossum officianale), is native to the United Kingdom, northern Europe and northern Asia. Takes its common name from the similarity between its leaves and the tongue of a panting dog. Leaves with veins resemble green tongues. Reddish-purple flowers grow in dense clusters. The leaves usually appear dusty and insect-ridden.
Houndstongue produces abundant seeds that are equipped with hooked barbs, enabling them to readily attach to animals, and clothing, facilitating their widespread dispersal. The plant's seeds and foliage contain toxic chemicals to livestock. 

What can I do?

So now that you know that these plants do not belong in your backyard, what should you do? To prevent the spread of weeds, you can pull them up by the roots, place them in a black bag and throw them in the trash. Do not compost them. Since every weed is different, the state of Colorado has a Noxious Weed Act that requires the Department of Agriculture to create and implement management plans for all weed species.

An integrated weed management approach is essential for effective weed control. This approach evaluates the most suitable techniques for a particular species, including manual (mowing, pulling, digging), cultural (adjusting land management practices like irrigation, cultivation, and cover crops), biological (using native plant pests), and chemical (herbicides).

The Department of Agriculture collaborates with all 64 counties in Colorado to manage noxious weeds. If you're struggling with weed control in your yard, the Eagle County Conservation District has a variety of programs and information to provide you with assistance and guidance.

Ivett Lopez Garcia is a naturalist at Walking Mountains who enjoys hiking in the Rocky Mountains, enjoying the beauty of nature.