Canada Thistle

Canada thistle, a noxious weed common in Colorado, is an aggressive and creeping perennial that spreads from its root system. Shoots become 1 to 3 feet tall and its purple flowers are about the size of a dime. It can also be recognized by its spiny leaves and stems. Hand pulling Canada thistle isn’t an…

Bindweed Control in Lawns

Field bindweed (Convolvulus arvensis) is a common problem in Colorado lawns in summer. Bindweed and other weeds don’t compete well in a dense, healthy, well cared-for lawn. This deeply-rooted perennial member of the morning glory family will quickly take over unhealthy, malnourished lawns suffering from drought stress or poor irrigation coverage. The first steps towards…

Controlling Bindweed

Field bindweed is a noxious perennial weed that is difficult to kill because of it’s extensive root system. It has distinctive arrowhead-shaped leaves and white or pink flowers. Bindweed grows along the ground until it encounters an object that it can climb, such as fences or other plants. Hand-pulling well-established bindweed generally does not kill…

Herbicides: Pre-Emergent

Pre-emergent herbicides or “weed preventers” are often used to control annual lawn weeds such as crabgrass, foxtails, barnyardgrass, spurge, knotweed, purslane and others. Examples include various “crabgrass preventers” on the market. A pre-emergent herbicide does not prevent weed seed germination or kill the seed. Instead, the root system development of a young weed seedling is…

Top Invasive Ornamentals in Colorado

Invasive ornamental weeds, because they are so much more attractive than some of the other noxious weeds, are less likely to be seen as problematic plants. “But they are so pretty,” people cry. Perhaps, but these pretty plants are just as destructive to native ecosystems as their uglier friends There are at least fifteen plants…

Landscape Weeds: Basics

Landscape weed control requires a three-pronged approach: prevention, cultural and chemical control. Weeds are opportunists. If there is an area in the yard with little or no vegetation, or if the vegetation is highly stressed, weeds will flourish. Their adaptability to difficult growing conditions is what makes us call them a weed.   Prevent weeds…

Blue Mustard Control

Blue mustard is a winter annual that germinates in late fall or early winter. It overwinters in a rosette and resumes active growth in the spring. Mature seed is produced by early summer. Blue mustard has bluish-purple flowers that leave small bean-like seed pods. The best time to control blue mustard with herbicides is in…

Why So Many Weeds?

Gardeners often ask why they have so many weeds. The answer is quite simple, we plant them!   Weed seeds can blow in, wash in with surface water, or be introduced with the application of soils and organic matter, like manure. Birds and other wildlife also distribute weed seeds. However, the majority of weeds come…

Colorado Noxious Weeds

Aliens have invaded the Colorado landscape! These aliens are in the form of non-native weeds called “noxious” in Colorado. They’ve gotten that name because of their invasiveness, aggressiveness and the rate in which they spread. Noxious weeds are difficult to control, and most are very adaptable. They also can withstand a variety of harsh conditions,…