It’s easy to get hooked on flowers that are easy to grow, especially those that seem to be refreshingly trouble-free. Unfortunately, some of these qualify as invasive ornamental weeds, and their rapid growth causes a multitude of problems. These undesirable plants reduce native plant habitat, reduce habitat for wildlife, alter riparian areas, and cause problems in agricultural lands. Colorado Noxious Weeds are illegal to grow, even though they may be available on the internet and in some “big box” stores. Following are three Noxious Weeds to watch out for, and native and non-invasive alternatives you can grow instead.
Noxious Weed: Purple Loosestrife. Here are some good alternatives:
Mojave Sage (Salvia pachyphylla) – Plant Select®, 2005: Mojave Sage is an intensely aromatic, evergreen foliage with great substance. Silver-green leaves set off persistent flowers. Shrubby perennial, xeriscape. The City of Lakewood has name Mojave Sage as the official city plant.
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| Salvia pachyphylla, Mojave Sage |
Rocky Mountain Penstemon (Penstemon strictus) - The tall showy spikes of intense blue-purple flowers last for over a month in late spring. Penstemon strictus is one of the longest lived, most easily grown of the Penstemons.
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| Penstemon strictus, Rocky Mountain Penstemon |
Noxious Weed: Dame’s Rocket. A good alternative is Pink Wild Snapdragon (Penstemon palmeri): heat tolerant beardtongue, native to NM and AZ. One of the few fragrant Penstemons, it blooms with gigantic spikes of large, light pink flowers in early summer. Must be grown in sandy or gravelly soils, not in tight clay. Best in a dry location.
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| Penstemon palmeri, Pink Wild Snapdragon |
Noxious Weed: Bouncingbet. Good alternatives include:
Rocky Mountain Bee Plant (Cleome serrulata) – This annual will grow two to five feet tall. Bees and insects enjoy the nectar from the blossoms, and seeds are often consumed by morning doves.
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| Cleome serrulata, Rocky Mountain Bee Plant |
Purple Coneflower (Echinacea purpurea) – Available in a variety of colors, a favorite in many Colorado gardens.
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| Echinacea purpurea, Purple Coneflower |
Check out the Colorado Department of Agriculture Noxious Weed Species webpage for images of noxious weeds found in our state.