The Iowa Gardener: Prepare to do battle with bindweed

There is only one weed in my garden that if I see it, I will immediately drop everything and yank it out: Bindweed. Nevermind if I’m late for an appointment, or I have my best clothes on, I will wade into my flower bed and pull out the offending plant. It’s that noxious.

Like so many of the worst weeds, bindweed is allowed to gain a foothold in yards because it can be so pretty. A cousin of morning glory, bindweed (Convolvulus arvensis) is often called wild morning glory. Its vine looks very similar, and if you allow it to flower — please don’t, since that allows it to produce seeds — it has pretty, morning glory-like flowers in white or creamy pink. People allow it to bloom, charmed by this demon vine’s innocent-looking beauty. But allow it to flower and it can take over an entire section of your yard.

The leaves are about 2 inches long and are sort of like the heart-shaped leaves of morning glory, except more elongated, so they’re closer to an arrowhead shape. The vine can easily grow 10 feet.

Classified as a noxious weed in Iowa and other states, bindweed left unchecked can form tangled mats, run along the ground or twist and twine around other plants, smothering them. I recently had to save a planting of several lilacs at our family farm that had been neglected, the bindweed had cloaked them and was suffocating them. Each bindweed plant can produce up to 500 seeds that remain viable for 50 years.

It is a native of Europe and Asia that first was documented in 1884 in San Diego, California. Within 50 years, it was proclaimed as the worst weed in California, as well as many other Western states.

The plants are perennial and start becoming noticeable around early summer and continue through frost. They start out as thin, threadlike vines that wrap and wind through shrubs, other perennials, fences and just about anything else that will lend support.

Even though I continually pull my bindweed, I still have it each year in my garden. It has a large and very hardy root system, so you can pull up a plant several times before it is truly killed. I had one spot near a corner of my house where a single bindweed plant would crop up, year after year. I would pull it out a couple of times a year, and it still took three or four years before it was completely eradicated.

You can control bindweed by pulling it whenever you see it. You will need to make several attempts on a plant to eventually kill it. Some gardeners swear by pouring boiling water on the roots after they pull the plant, but it seems to have limited effectiveness and it sounds like a hassle to boot.

I try to use as few chemicals as I can in my garden, but one option is to spray an herbicide like RoundUp on the plant when it is no more than 1 foot tall. But since RoundUp kills all plants that it touches, this is impractical for bindweed that’s infesting a flower bed or climbing up a shrub.

Do not hoe bindweed. That just chops it up and allows the bits and pieces to sprout in the soil, spreading it.

If you have bindweed in your lawn, that says something about your lawn. It usually isn’t a problem where the grass is healthy and crowds out weeds. But if you have bare spots, bindweed may be taking advantage of the open ground. The best way to deal with the bindweed in that case is to keep the lawn well-mowed, well-watered, and to fertilize regularly to encourage thick grass that crowds out weeds. If you apply a broad-leaf herbicide to your lawn, that will help with bindweed control. In fall, reseed bare areas and keep well-watered for at least two weeks until new grass establishes itself.

Veronica Lorson Fowler is co-publisher of The Iowa Gardener website at theiowagardener.com.