Kariann,

Here's some information I have previously prepared regarding this weed. It is a source of frustration for many and there are unfortunately no easy solutions. 

Please look this over and let me know if you have any questions.

*Note, I will be out of the office June 4-20, so I may not be able to respond during that time. I apologize for the inconvenience.
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Field bindweed (Convolvulus arvensis) is an introduced perennial plant in Michigan. It has a deep central taproot (sometimes 20’ or more) and spreads by rhizomes (underground stems) and seed. Field bindweed has opposite, arrow-head shaped leaves with generally rounded tips. Flowers are funnel-shaped and white or sometimes pink in color.

Because of the rhizome system, this weed is a very tough weed to control. The following are some options to try, and repeated efforts will likely be needed. Whatever strategy or combination you choose, it is best to act before they flower and produce seed to avoid furthering the infestation.

Persistent physical removal of the aboveground plant material, rhizomes, and roots will eventually deplete the plant of resources, but it could take several years of this to achieve success.

Repeated tillage (not appropriate for your area) could be used to deplete the plant of resources. Tillage can also spread the plant around as small rhizome fragments are chopped up and moved.

In some cases, we recommend the use of dense landscape fabric or tarps on the soil to shade out the bindweed, particularly if the material is laid and then covered with mulch. Any holes cut in the fabric for desirable plants may allow bindweed a new avenue to emerge. Complete death via light deprivation is reported to take between 3 to 5 years.

A non-selective herbicide, such as glyphosate (e.g. Roundup Super Concentrate, though there are several other products available. You may find generic glyphosate much cheaper somewhere like TSC) can be effective in controlling field bindweed, but care would be needed to avoid your desirable plants. With many perennials you can cut the plant and apply concentrated glyphosate on the cut surface immediately after (<5 min) using a cotton swab or other means. This method helps avoid contacting nearby desirable plants. Late summer to early-fall timing is when glyphosate has the greatest efficacy on perennial weeds because the plants are moving resources to the root system.

When using products containing glyphosate there are a few important points to consider. First, as with any pesticide, remember to read and follow all labeled instructions. Second, glyphosate is a broad-spectrum herbicide, meaning it will injure or kill other plants contacted during application, so care is needed to avoid green plant material, exposed roots, and injured bark of desired plants. Third, glyphosate is relatively safe in the environment when used as labeled. It adsorbs strongly to soil in most cases (i.e. clay and organic matter), allowing even sensitive crops to be planted shortly after application; meaning no carry over issues are expected. Fourth, glyphosate alone can take up to 14 days to show full activity under ideal growing conditions. Retreatment of the area may be needed depending on the degree of infestation. Glyphosate is most effective for perennial control in the fall, as previously mentioned, but can be applied anytime the plants are actively growing (temperatures consistently above 50F). Finally, be sure that the product you choose has only the active ingredient glyphosate. Products with additional active ingredients may have other unwanted effects and may delay the planting of other plants in the coming season(s). Glyphosate is mixed with another active ingredient pelargonic acid in the ready to use Roundup Weed & Grass Killer. This would not be recommended. While you'll get good tissue death, the pelargonic acid kills the tissue too quickly, not allowing the glyphosate to be fully translocated (moved within the plant).