Field bindweed is difficult to control, especially for homeowners, but there are options.
Home Vegetable Gardens: Weed control requires taking the treated portion of the garden out of production for a time.
Glyphosate - Glyphosate is sold under a wide variety of names, the most common being Roundup. Take the garden out of production when treating.
1. Glyphosate is a non-selective herbicide that will kill whatever it hits but is inactivated when it contacts the soil.
2. Glyphosate is most effective when applied to bindweed that is at or beyond full bloom. You can treat earlier but don't skip the late summer to fall application.
3. Do not apply to bindweed that is under moisture stress or not growing well.
Turf: Selective herbicides are available. An herbicide with the trade name of Drive (quinclorac) is now packaged in homeowner combination herbicides such as Fertilome Weed-Out with Q, Ortho Weed-B-Gon Max + Crabgrass Control, Monterey Crab-E-Rad Plus, and Bayer All-in-One Lawn Weed and Crabgrass Killer.
Commercial applicators can also use Drive (quinclorac) as well as Q4 (contains quinclorac). Products with Drive work better than glyphosate and are selective. Note that lawns treated with Drive should not use clippings in compost or as a mulch since Drive is very stable on grass clippings. We recommend clippings be returned to the lawn anyway but if they are bagged, they should be discarded. Do not apply products with Drive over exposed roots of trees and ornamentals. It would be best to avoid spraying beneath the canopy of any trees to avoid possible damage. If there are plans to convert a section of lawn to a vegetable garden, do not use Drive on that area. Eggplants can be damaged if planted within 12 months of areas treated with Drive, and tomatoes can be damaged if planted within 24 months. Shrub Beds: Use a spray of glyphosate between plants. Use a shield if spraying near plants to keep spray from contacting green plant material. Remember, glyphosate will hurt your shrubs if it contacts green tissue.
It is possible to control field bindweed by pulling, but you must be extremely persistent. I remember reading a study from the 1940s that found that bindweed produces enough energy to start strengthening the roots when it reached the six-leaf stage. So, if pulling, never allow plants to produce more than six leaves.
Lauren Fick is the Horticulture Extension Agent for the Cottonwood Extension District. If you have questions, she can be contacted by e-mail at [email protected] or by phone at 785-628-9430 or 620-793-1910.