Traditional Methods for Controlling Field Bindweed
or wild Morning Glory can be a most difficult weed to get the upper hand on. It is a very hardy perennial broad-leafed weed that requires plenty of chemical and correct timing to have any success at control. Bio control measures on bindweed are out on the horizon, but not an effective tool to date. Bindweed can be found mentioned in some of Utah's earliest weed irradiation guides. If left alone for a few seasons, the dense rood structure can make deep tillage almost impossible. Fortunately, we have some very effective herbicides available today. Once again, it is extremely important that you READ AND FOLLOW THE LABEL with any herbicide you chose to use. The "time line" featured near the bottom of the page represents a generalized guide to the most effective timing of chemical weed control here in Northern Utah.
Bindweed is a very stubborn perennial weed and it thrives in non-crop sites. Once the decision has been on bare ground or selective weed control, the rest is a matter of timing. If grasses are not to be taken out, the best selective herbicide is Banvel® mixed with a little 2,4-D. It is very effective IF the timing is right. Best control is had when the flower is full open, particularly in late fall just before killing frost.
For bare ground, we like Arsenal® or Oust® tank mixed with diuron for most all bare ground jobs. Using a tank mix like this one will help ensure that resistant weeds such as kochia will not take advantage of the situation and sprout back with a vengeance. Timing gets to be a problem when trying to take utilize the dual action properties of Arsenal® or Oust®. The best time to kill perennial weeds through folar action is when they are mature and flowering. Very little rainfall is available at that time of year (middle June on) to incorporate the herbicide into the ground for root uptake. So, if all you are going to get is folar action anyway, perhaps Roundup® (see below) is the most cost effective choice. See labels for rates on your soils. CAUTION Watch sloping ground for potential runoff in the event of heavy rain or overhead irrigation!
Roundup® plus Banvel® may be the best non-selective bet on Field Bindweed, particularly if the infestation is solid and a few years old. A 2 quart rate of Roundup® plus a pint of Banvel® is effective and a good surfactant is a must! After the initial big hit with this mix, a bare ground tank mix early enough in the following season to assure sufficient rainfall ought to finish the job. Again, timing is everything! Don't waste your Roundup® on actively growing Bindweed in June ....... it is just too early. Mowing is not acceptable as a control measure because the weed is perennial and will still be there when the snow flies. And as you might imagine, the very fine seeds are easily spread via the implement to other non-infested areas.
Rights of Way
Irrigation ditches and streams pose the usual concerns when trying to target bindweed next to them. Arsenal® or Telar® are widely used along concrete irrigation ditches to control damaging perennials but overspray into the irrigation stream must be avoided. Tordon® is not a good choice anywhere near water. Roundup® or Rodeo® are also very good in these situations and chemical allowed in the water is of little downstream consequence. You put a pencil to the rates and use the one that is cost effective for your budget.
Along roadsides, we find that the usual treatments of Campaign® or 2,4-D and Banvel® will usually keep Field Bindweed in check. If a dense patch becomes a concern, a spot treatment with Tordon® should eliminate the problem.
Most labels for herbicides used in crops do specifically mention Field Bindweed as a target weed. Croplands in production will not generally be troubled with either one of these weeds if good farming practices are applied. If rowcrops or alfalfa are being considered for a piece that has been infested with bindweed, might be a good idea to plant cereal grains the first year, make the young grain weed free with your favorite chemical, and follow up after harvest if any late weed sprouts appear with Roundup® or 2-4,D. Then the following year, the tillage and/or chemical treatments you would normally use on rowcrops or alfalfa should keep any remaining invaders in check.