Archive for Saturday, July 8, 2017

Garden Variety: Battling bindweed no easy task

July 8, 2017


Weeds — those pesky unwanted plants that keep popping up in the lawn and garden — seem especially difficult to control in late summer. One in particular, field bindweed, is blooming and flourishing right now in the Midwest, and gardeners who have it know the special challenge of fighting it.

Bindweed is a major problem because of its extensive root system with reproductive buds, the ability for roots and seeds to remain viable in the soil for decades, and the plant’s interference with the growth of more desirable plants.

Bindweed might be a small annoyance in a flower bed, but left unchecked could cover and shade out plants. It is a little more annoying in a vegetable garden, where cultivated soil only seems to turn up new roots and seeds, and vines stretch to great lengths before being seen among the squash and cucumbers. For commercial producers, bindweed can cause substantial crop loss or yield reduction along with significant costs for control on a large scale.

Bindweed is identified by its dark green, dull, half-inch to two-inch long arrowhead or heart-shaped leaves. Leaves grow opposite each other along long, tender, viny stems. Bindweed is related to the prettier and less aggressive morning glory and is sometimes confused with it or with milkweed vine. Bindweed leaves are smaller and more abundant than these related species.

Bindweed is also identified by the white to pale pink flowers that are shaped like a trumpet’s horn. They are produced in abundance throughout the summer.

In mowed areas or areas without other vegetation, bindweed grows flat along the ground, but as soon as it contacts a plant or structure, it will use that for support to grow up and over.

Bindweed is easy to control by pulling as a very small tender seedling, but once it is established, it can take years of work to remove. Researchers suggest removing before the plant has 5 true leaves. After that, the roots begin producing reproductive buds and can re-sprout if the plant is pulled and roots break off. Root systems are reported to extend 30 feet deep or more in the right soil, and seeds can remain dormant in the soil for decades.

Repeated cultivation and pulling will eventually deplete the root system and is practical for a dedicated (stubborn) home gardener. Covering bindweed with black weed mat can be effective as long as light cannot penetrate — the University of Nebraska suggests the mat be left in place for three years to completely kill the plant. Solarization with clear plastic is ineffective as the bindweed will continue to grow even after weeks in the hottest part of the summer.

For gardeners or producers who need a larger-scale option, broadleaf-selective or broad-spectrum herbicides are the most popular choice. They are most effective in the fall when plants are storing resources in their roots, but may also make a dent on the plant in spring and early summer. Midsummer applications are largely ineffective. Also, one application may knock the plant back, but is unlikely to wipe it out completely. Plan to make multiple applications in the spring and fall each year for a few consecutive years at least.

— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation.


Ron Holzwarth 9 months, 2 weeks ago

An interesting tidbit - bindweed got its name from its tendency to wrap up and around the headers of early farm equipment and bind them up. Cutting and removal of the bindweed was then necessary before the implement could be used again, which was no easy task.

It was a serious problem for the early settlers, because the only method of fighting bindweed was repeated discing, which was only of limited effectiveness, and it needed to be done again every year.

In some areas of western Kansas and eastern Colorado it's very common, although you wouldn't notice unless you were looking for it. I've been told that in Colorado, the ditches of the highways are infested and there seems to be no attempt being made to remove it. That's hearsay from my brother though, I never noticed it.

Several years ago my father put some land into the CRP (Conservation Reserve Program) in western Kansas, which restores formerly cultivated fields back to native grassland, more or less. When the native buffalo grass was planted, bindweed already had a firm grip on the land. I was told that it will be impossible to remove it unless the field cultivated, thus rendering the bindweed vulnerable to herbicides again.

A couple more tidbits about bindweed - the wind does not seem to spread the seeds very far since they are rather small, they seem to travel on the hooves and paws of animals. And, the bindweed plant does not block much sunlight from other plants, unless the bindweed stand is very thick.

Just last year I noticed something interesting - there was bindweed growing only about a block from my home here in Lawrence. I haven't noticed it lately though, so it's possible that the herbicide used to remove dandelions (2-4-D) has eliminated it also.

There's one thing that's for sure - barring an asteroid impact or a supervolcano eruption, the bindweed plant will be with us for tens of thousands of years, a blip in evolutionary time. The bindweed plant has certainly evolved for survival against just about everything that nature can throw at it.

Carol Bowen 9 months, 2 weeks ago

Great history, Ron. Thanks for sharing. Too bad ljw didn't include a picture.

Hudson Luce 9 months, 2 weeks ago

Bindweed has some interesting medicinal properties: "The extract of bindweed is believed to arrest the growth of tumors, and its anticancer properties are presently being researched. Bindweed also exhibits actions similar to that of anti-diabetic medications as it is considered to inhibit the action of beta-glucosidase and alpha galctosidase. This, in turn, aids in lesser absorption of carbohydrates into the intestine, thus checking the blood sugar levels. Similar to sweet potato, the insulin-like compound in bindweed aids in effective diabetes management. Bindweed, especially its flowers, is believed to exhibit antibacterial and antifungal properties against a broad spectrum of microbes, including E. coli, salmonella species, and candida albicans." And it can be good for contaminated soil: "Bindweed finds other uses in restoring the fertility of agricultural land that has been subject to the extensive use of chemicals and pesticides. It is researched and believed to eradicate chromium, copper, and cadmium from the soil."

Here's a picture of it:

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