Seminole County OSU Cooperative Extension

Help! Weeds are Taking Over the Garden

If you have been on vacation or just not had time to get into the garden this summer, especially with the hot weather we have had, your gardens may be overrun with weeds. It doesn’t take long in Oklahoma for weeds to take control and create a real headache. Weeds in the flower and vegetable garden compete for nutrients, soil moisture, sunlight, and space with desirable plants. By this time of year, you are more likely to throw your hands into the air and walk away from it all. However, don’t despair because it is possible to regain control.

If your annual flowerbed or vegetable garden is going downhill fast, then you may consider starting over by killing everything in the garden bed. If you still have desirable plants that you want to save, then a different approach may be necessary.

 If you are willing to sacrifice what is left of the flowers and vegetables for sake of gaining control, then you can spray the garden with a product containing glyphosate, such as Roundup, Kleenup, Kleeraway, etc. glyphosate is a non-selective herbicide that will kill both grass and broadleaf plants. It breaks down quickly and is not active in the soil so you can replant in the area within a reasonable amount of time following treatment (usually as soon as the plants that were there have died and been removed). Apply while weeds are actively growing for best results.

  If you wish to save some of the plants in the garden, then you will need to determine what types of weeds you have. If they are broadleaf weeds such as dandelion, spurge, etc., then you are somewhat out of luck unless you want to pull them by hand. There are no postemergence, broadleaf herbicides available as over-the-top sprays that can be used in the ornamental or vegetable garden that won’t damage or kill your desirable plants. If the weeds are grasses, then you have some choices.

 Two chemicals, sethoxydim (Poast, Grass Getter, etc.) for use on ornamentals and certain vegetables, and fluazifop-p-butyl (Grass-B-Gone, Grass-Out, etc.) for ornamentals, are available as over-the-top sprays that will kill grassy weeds but not the desirable plants. However, like most pesticides, some damage may occur to some plant species, so it is best to read the label and make sure it is safe to use on your particular crops in your particular situation before purchasing.

 Next spring, and possibly even this fall, you will want to use a preemergence herbicide to control any weed seeds left in the garden, if you are not planning on starting new plants by seed. In most cases, if you are starting your garden by seed, preemergence herbicides can be used, but only after your plants have germinated and become well-established seedlings. A product containing trifluralin (Preen) is available for use in ornamental and vegetable beds. More than one application may be needed to provide season long control. 

 Once you have gained control again of your garden, it shouldn’t be as difficult to maintain. Staying on top of new weeds that pop up by occasional hand pulling, light cultivation, and the use of mulches should ensure a healthier, more productive garden in the future.

 As always feel free to contact your local county extension department at 450-257-5433 in Wewoka, or 405-379-5470 in Holdenville and we will be glad to answer any questions you may have.


Oklahoma State University, U. S. Department of Agriculture, State and Local Governments Cooperating.  The Oklahoma Cooperative Extension Service offers its programs to all eligible persons regardless of race, color, national origin, religion, gender, age, disability, or status as a veteran, and is an equal opportunity employer.

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