Bindweed in Bloom–Show No Mercy

Bindweed’s trumpet-shaped flowers are about an inch wide. After flowering, the plant moves into the seed-forming stage. (Photo courtesy of Tom Heutte, USDA Forest Service, Bugwood.org)

Bindweed.  You’ve seen it. It’s everywhere–little morning-glory-like flowers on vines with elongated, arrowhead-shaped leaves.

This ubiquitous plant enjoys a well-deserved reputation as a noxious weed, with a mugshot on the Colorado Department of Agriculture’s noxious weed page, and a listing on the Colorado Weed Management Association website.

Why does bindweed resemble a morning glory?  Because it’s a member of the genus Convolvulus, which includes the beautiful garden-variety morning glory. But while the Cinderella version is an annual, bindweed (the ugly stepsister) is a perennial that blooms from May through August.  After blooming, bindweed produces seeds that can remain viable for 50 years or so, providing generation after generation of these invasive vines. The invader spreads by both seeds and roots, which reportedly extend as far as Nebraska and the Chinese mainland (just kidding). 

Bindweed’s vines can grow up to five feet long and can strangle desirable plants, including shrubs. (Photo courtesy of Howard F. Schwartz, Colorado State University, Bugwood.org)

There’s no getting rid of it completely, but there are ways to control the plant’s spread.

• Don’t let it go to seed. The minute you see a vine in flower, remove it. Some sources say to just pull it; others say that you should cut the vines off at ground level because pulling encourages additional growth. You decide. You can also use a hoe or weeding tool to dig out as much root as you can. Don’t leave pieces of bindweed in the soil, though, because plants can regenerate from small pieces.
• Whenever you seen a bindweed vine, whether it’s in bloom or not, remove it as soon as possible. By depriving the plant of foliage and the ability to photosynthesize, you’re weakening the plant.
• You can use chemicals, particularly quinclorac, to reduce the vine’s spread. Be sure to read the active ingredients on the front of the herbicide bottle. You’ll find quinclorac in Spectracide Weed Stop for Lawns Plus Crabgrass Killer. Picloram (Tordon), as well as dicamba (Banvel), have also been found to be effective against bindweed, according to The Nature Conservancy. But they’re more expensive than quinclorac. If you’re interested, you can read The Nature Conservancy’s report for yourself. 
• Bindweed mites are another means of control. The Colorado Department of Agriculture’s Palisade Insectary provides them. However, their availability is limited in Colorado. According to a July 15, 2015 release by the Fort Collins Conservation District, the district isn’t taking any more bindweed orders until it has filled those for existing customers. The situation may be the same in other counties.
• In lawns, discourage bindweed by increasing the density of your grass. Fill in bare spots and overseed your lawn every spring or fall, if needed.

Bindweed is a curse that almost every C0lorado homeowner must live with. But by preventing it from going to seed and removing existing plants, you can get a handle on it so it doesn’t take over your lawn and garden.