Tips for Controlling Weeds in Tall Fescue Pastures and Hayfields

Controlling weeds will be important for pastures and hayfields recovering from last year’s drought in Tennessee and across the southeast.

Since the drought, I have been receiving lots of questions about what to expect from this spring’s hay and pasture fields. We may not have an answer to that question until this spring when warm temperatures allow our grasses to start growing again. One thing that will be important this year is to control weeds in our fields. By doing this, it will allow grasses to stand a better chance to re-establish not having to be in competing with the weeds.

Weeds are considered one of the biggest problems in tall fescue pastures and hayfields across the state. Buttercup, musk thistle, buckhorn plantain and horsenettle are just a few of the weeds that can move quickly into fields and cause production losses. There are several ways to minimize the problems caused by weeds.

Correct stand and soil fertility problems.

Weeds move into fields because they can outcompete the existing plants. We have all seen thick, aggressive stands of tall fescue that have little weed pressure – there is no space for a weed seed to germinate and grow. To minimize weed pressure, you have to have a strong stand of grass. You may kill all the weeds this year, but if large portions of the ground remain bare, a new crop of weeds will germinate and grow. Be sure that poor soil fertility is not the reason for the poor stand. A soil test will give you the information needed for proper fertilization and liming. Soil test and follow the recommendations now. Once fertility problems are corrected, evaluate the stand of grass. If it is weak, consider replanting this fall.

Identify the weeds before using herbicides, know the specific weeds you are trying to kill.

Certain weeds are more difficult to kill, so herbicides, application timings and rates may vary. If you don’t know the name of a weed, bring a sample to your local Extension office for help in identification and specific herbicide recommendations. Spray at the appropriate time. Knowing whether a weed grows during the winter or summer is essential in knowing the proper time to spray with a herbicide. For winter weeds such as buttercup, musk thistle and buckhorn plantain, a herbicide should be sprayed during either December or March for adequate control. After two to three days of warm weather, the weed will be growing enough to take up the herbicide and be controlled. Some weeds such as horsenettle, pigweed and cocklebur only grow during the summer (May to October or November). The winter or spring application will not adequately control them, because they are not up yet. A late May or June herbicide application is needed for these weeds. Summer sprays are more difficult, mainly due to all of the sensitive crops that are around. Soybeans, tomatoes and tobacco can be severely damaged by drift from herbicides. Know the surrounding crops before using herbicides, particularly during summer.

Select the proper herbicide.

Many herbicides are available; be sure to use one that is labeled for pasture and hay. It is illegal to use any herbicide on pastures and hayfields that has not be tested and approved for use. Just because it works does not mean it is safe. Read and follow all label instructions when using herbicides. Many weeds can be controlled adequately with 2,4-D. Buttercup and musk thistle can be almost totally controlled with a 2-pints-per-acre application. If buckhorn or broadleaf plantain is present, increase the rate to 4 pints per acre. This higher rate will take out both red and white clover. If applied in December, clovers can be replanted in February or March. For weeds that are more difficult to control, particularly summer weeds such as horsenettle and tall ironweed, new herbicides such as Forefront, Grazon and PastureGard are available. Specific recommendations will depend on location of your farm, the weed, and other factors. Following these recommendations should help you minimize weed growth and improve the yield of your pasture and hayfields.

W. Alan Bruhin – Extension Director