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If you visited our office last summer, you probably noticed various plants on the counter, displayed in vases with labels stating their names and a designation: "Native," "Noxious Weed," or "Weed, NOT noxious," which we will hereafter refer to as "Obnoxious."
The plants on display could ALL have been considered "weeds," but depending on their designation, TCWP would treat them very differently. Why is that?
First, let's define "weed." Easier said than done! The most general and inclusive definition of a weed is any plant growing where it is not wanted. Therefore, grass growing in your strawberry patch is a "weed," but grass growing in your lawn is not. It is more helpful to expand this definition: A weed is a plant growing where it is not wanted, and growing aggressively, due to its possession of certain "weedy" characteristics. Those characteristics include:
1. They are "pioneers" that capitalize on disturbed areas and grow very quickly
2. They are prolific reproducers, putting out millions of seeds each year and/or reproducing vegetatively through extensive underground root systems
3. They are very tolerant of poor quality environments and can survive and thrive in undesirable habitats like road-cuts and parking lots
4. They are often unpalatable and sometimes even poisonous to local animals
5. They are not native to the ecosystem, and therefore have no co-evolved predators
All of the above traits make weeds highly competitive with native plants!
Based on these characteristics, let's investigate "weeds" that are native, noxious, and just obnoxious.
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Common Yarrow is a native plant that is very competitive and
often considered a "weed"
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Natives
There are many species of native plants that are widely considered to be weeds because they have one or more of the weedy characteristics listed above. Common Yarrow, Curly-cup Gumweed, and Long-leaved Aster are native plants in the Aster family that are very good competitors and thrive in challenging environments. These plants often appear in dry, gravelly soils, along the right-of-way of roads, and in disturbed areas. In a well-watered yard, these species will also do well, and may out-compete other more desirable plants.
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| Curlycup Gumweed is a native plant that is often found in overgrazed rangeland and roadsides and many consider it a weed |
Lupine and Larkspur are native plants with beautiful purple flowers that ranchers consider weeds because they are toxic to livestock. They are occasionally eaten by native wildlife.
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Larkspur is a native plant that is toxic to cattle and therefore considered a weed by ranchers
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Here at TCWP, native plants are usually not treated as weeds. We view them as highly-evolved species that - at this point in time - have a competitive advantage over their peers. Ecological competition is a natural process that drives evolution, and if native plants are out-competing other native plants, it is not our role to interfere. We usually do not condone the treatment of these "weedy" natives. They are not considered "noxious."
"Noxious Weeds" are the only weeds we concern ourselves with at TCWP. To have the unfortunate designation of "noxious," a weed must be non-native AND cause significant harm to ecosystems and/or agricultural systems. They do this by invading and displacing native forage and/or agricultural crops, causing significant loss of habitat as well as economic loss.
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Spotted Knapweed is considered a noxious weed because it invades healthy native plant communities and changes the soil chemistry, making the soil unfavorable to native plants. Eventually, the previously diverse native community will be replaced with one species - Spotted Knapweed!
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Weeds like Leafy Spurge, Salt Cedar and Spotted Knapweed are known as "habitat transformers" because they change the physical structure and forage availability in habitats, eventually pushing resident wildlife out. There are currently 26 species on the Wyoming State Designated Noxious Weed List, and an additional 26 on the Teton County Declared Noxious Weed List. To see these lists, click
here.
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Dalmatian Toadflax is the yellow flower that is crowding the native sagebrush and Fireweed in the foreground. Toadflax is a noxious weed that can also be a problem in agricultural settings, where its under-ground root system may get caught in the plow, further spreading the infestation
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OBnoxious Garden Weeds
These are considered weeds because they have some of the above characteristics and they are non-native. However, they are not considered "noxious," because they do not invade and displace healthy native plant communities. Examples include Dandelions, Salsify, Yellow Sweetclover, and Field Penny Cress.
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Salsify is a notorious garden weed that infuriates landowners with its large, globular seedheads that fill the skies with seed on a windy day
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People often come into our office complaining about these weeds because they find them in their gardens, flowerbeds and lawns. Although it is frustrating to see your yard filled with dandelion seed-heads, prepared to blow their progeny into every crack and cranny of your property, dandelions and the like are really the least of your weed worries. They are in your yard because you created ideal habitat for them there. They wouldn't survive as well in the sagebrush steppe.
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| Field Pennycress is one of the countless weeds in the Mustard family that pop up in gardens each spring. Though obnoxious, they do not present a real problem, and like all mustard species, they are edible! |
These weeds are not considered noxious because they don't disrupt natural ecological settings. Instead, they co-exist with other native plants, are often eaten by wildlife, and may eventually receive the designation of "naturalized."
So kill them if you must, but we would rather you reserved your time and energy for the real criminals - the noxious weeds!
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