5 Common Weeds in Colorado and How to Manage Them
They say a weed is a plant growing where you don’t want it to grow. While that may be true, some are weeds with a capital “W”. They are prolific and grow in any space available. They steal resources from lawn and cultivated plants and, in some cases, out-compete them. Here is a list of five common weeds I’ve found and identified in my own yard and ways to manage them. By no means is this a complete list of weeds in my yard. It’s a sample of the types of weeds found in the greatest numbers on my particular suburban property.
I’m currently using a combination of hand pulling, mowing, weed whacking (literally), and mulching to deal with these weeds. As you’ll see below, some of these methods are better than others but it depends on the weed species. I have not included chemical methods of weed removal in this post but information can be found in the reference links.
Some weeds have been deemed noxious weeds by the Colorado Department of Agriculture (CDA). “The aim of the Noxious Weed Program is to control noxious weeds, the non-native aggressive invaders that replace native vegetation, reduce agricultural productivity, cause wind and water erosion and pose an increased threat to communities from wildfire.” Noxious weeds are classified as A, B, C, or Watch Species, depending on the threat level. (Colorado Department of Agriculture – Noxious Weeds)
Field Bindweed
(Convolvulus arvensis)
CDA Noxious Weed List C
Field Bindweed is the most common of the weeds in my yard and is my personal nemesis. This vining weed is a perennial, meaning it regrows year after year. It has arrowhead-shaped leaves and blooms with deceptively pretty white flowers. Bindweed reproduces by seed and roots that can grow up to 20 feet long! Take the following steps to protect your lawn and garden from this savage.
Leave no bare soil. Plant the garden thickly or use mulch generously. Mind you, it’ll probably still grow but not nearly as much as it does on bare soil.
Hand-pull or snip the stems at ground level. Be sure to throw all pieces into the trash because each piece of bindweed can root and make more baby bindweeds. Repeat, repeat, repeat. By removing the aboveground leaves repeatedly, you’ll eventually wear it down and it’ll give up.
Get your hands on some bindweed mites! This sounds easier than it is.
First, sign up for the waitlist here: Request A Bug.
Once released, these mites feed on bindweed, eventually causing it to die. However, that can take a few years to happen. (Colorado State University Extension – Bindweed Mites)
Dandelion
(Taraxacum officinale)
Dandelions are a favorite of wishing children and can launch over 100 seeds with a gentle puff of air. They grow low to the ground and have yellow flowers that dot lawns all across America. In addition to reproducing by seed, these perennials have root fragments that can regenerate. Unlike bindweed, however, it is possible to remove the entire root.
Remove flowers before the seed stage. Once dandelions form the puffballs, they can multiply exponentially.
Remove the entire plant, including the root. Dandelion plants can regenerate from partial roots left behind.
Leave no bare soil. Mulch generously to prevent seeds from germinating.
Perennial Pepperweed
(Lepidium latifolium)
CDA Noxious Weed List B
Perennial Pepperweed is, in fact, perennial with roots as long as 10 feet. The long root system draws salt up through the plant where it is excreted onto the topsoil. Doing this changes the salinity of the surrounding soil and affects the health of your garden plants. It reproduces primarily from root pieces and, to a lesser extent, by seed.
Control by mowing or clipping at the soil line. Perennial Pepperweed can reproduce from small root fragments so don’t disturb the roots!
Of course, I’ve been doing it wrong by hand-pulling and trying to remove the roots. That explains their recent success in my yard. From now on, I’ll cut the plant at the ground surface and solarize the areas with the heaviest infestation to kill the seeds. (Colorado State University Extension – Soil Solarization)
Common Mallow
(Malva neglecta)
Common Mallow or cheeseweed is another nemesis weed for me. The branching root structure makes digging it out quite the excavation exercise which may not make much of a difference. Common Mallow is classified as an annual (lives one year) or biennial (lives for two years) and only reproduces by seed.
Control this weed by hand pulling. Do this before it goes to seed, removing a good chunk of the taproot, if possible.
Leave no bare soil. Plant the garden thickly and/or use mulch generously.
Canada Thistle
(Cirsium arvense)
CDA Noxious Weed List B
Canada Thistle is a perennial that reproduces by seeds and spreading roots. It’s quite prickly and forms a beautiful lavender-colored flower. Canada Thistle is a late arrival to the weed party in my yard but quickly gaining in numbers. It’s no wonder since I assist in their propagation by hand pulling and probably leaving roots in the ground. {sigh}
Mow or clip frequently. Doing so will stress the plant without disturbing the root.
Leave no bare soil. Plant the garden thickly and/or use mulch generously.
Weedy Wrap-up
Unfortunately, weeds are a very real, and often annoying, part of gardening. As you can see, the management method can vary greatly depending on the weed species. It’s important to identify the weed in question so it can be managed in the correct way. Researching and writing this post has given me a game plan for minimizing, or at least not spreading, the weeds in my yard. I hope it benefits you, as well!
References
Colorado Department of Agriculture: Field Bindweed Identification and Management
Utah State University Extension: Dandelion
Colorado Department of Agriculture: Perennial Pepperweed Identification and Management
Utah State University Extension: Common Mallow
Colorado Department of Agriculture: Canada Thistle Identification and Management