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Larry A. Sagers Extension Horticulture Specialist Utah State University Thanksgiving Point Office All Rights Reserved
FIELD BINDWEED (Wild Morning Glory)
Field Bindweed or wild morning glory is also known as creeping jenny and several other less complimentary names. This weed is often confused with the annual morning glory. The scientific name of field bindweed is "Convolvulus arvensis" while annual morning glory varieties are "Ipomea" and are closely related to the sweetpotato.
Field bindweed was introduced from Europe and is a serious problem throughout the world in both cultivated fields and non cultivated areas. It is adapted from low desert to elevations up to 10,000 feet. It is troublesome to eradicate because large, deep, tap roots penetrate the soil to a depth of 10 feet or more and form long, extensive rhizomes which spread the plant. It produces abundant seeds that stay in the soil for 20 years or more.
Bindweed is a serious problem, but control is possible. Complaining about the problem instead of doing something about it guarantees the weed will spread and be worse next year.
Chemical control is best done prior to the time any crops are planted. This is particularly true if perennial crops, including raspberries, strawberries, grapes, ornamental shrubs and perennial flowers are to be planted. Delay planting to get bindweed under control if that option is available.
Glyphosate is the safest chemical to use in and around desirable plants. It is non-selective and affects both broadleaf and grassy plants and roots. It also has a low human toxicity so it is safe to use. It is readily available in several forms including Roundup or Killzall. It must be more concentrated than usual to control bindweed so follow the dilution rates used for brush or woody plants.
Ready to use formulations of glyphosate are too diluted to have an effect on bindweed. Spreader sticker added to the spray solution increases the effectiveness.
Field bindweed control is often enhanced by adding the recommended dose of lawn weed killer or other forms of 2,4-D or Trimec. Do not use this combination if you intend to plant a garden in the treated area in the same year and do not use it among desirable plants.
Repeated treatments are often necessary. Apply the sprays carefully because herbicides kill desirable plants and spray that hits the soil is wasted. Spray bindweed when it is actively growing. The more foliage present, the more effectively the chemical is absorbed and translocated throughout the plant.
Bindweed under stress from drought or covered with dust will not absorb the herbicide and control will be very poor. Do not spray within 8 hours of expected rainfall or sprinkler irrigation.
Sprays are also effective in the early fall, around the time of the first frost. At that time, the plants move the sugars and protein materials from the leaves and stores them in the roots. Applying herbicides at this time help it translocate to the roots. If the roots are destroyed the weeds are controlled.
Glyphosate is registered for preplant treatment of most crops. Most annuals and perennials can be planted within seven days after spraying. With severe infestations, it is better to retreat if necessary. Single applications reduce the infestation but do not eradicate the weed and follow-up treatments are necessary.
Bindweed control in established plantings is much more difficult. Selective treatments must be applied carefully so that the herbicide contacts the weed but does not get on desirable plants. Spray bottles, sponges, or paint brushes are often used to apply herbicides. Apply herbicide to bindweed growing in desirable plants by using a cotton glove over a rubber glove.
Dip the glove into weed killer and wipe onto the leaves. Commercial equipment is also available to wipe the herbicide on the weeds. Solutions applied this way should be at least three times as strong as the solutions listed in the chart.
Alternatively, long strands of bindweed can be physically separated from ornamental plants and laid on newspapers spread over the top of the plant. Spray the bindweed carefully, allow it to dry, and then remove the newspapers. This protects desirable plants while allowing good contact with the weedy vines.
Well managed turf makes bindweed control easier. Maintain a vigorous, healthy lawn by fertilizing, watering, and mowing regularly at 2 to 3 inches high. Lawn weed sprays of 2,4-D, Trimec, or Turflon are effective against bindweed