Horse Pasture Weeds

             (Photo courtesy of NCSU Turffiles)

Last spring, did you have beautiful yellow flowers covering your pastures?  Although these flowers, commonly known as buttercup, are pretty to look at, they have no nutritional value and can take important nutrients from the plants you are trying to grow in your pasture.  This weed, which is a winter annual, should be sprayed in late winter or early spring (late February – early March) for the best kill.  So, now is a great time to scout for those weeds.  With the warm temperatures this winter, you may be able to see small rosettes of this weed poking through the grass.  If you wait until they are blooming to spray, you will be wasting your time and money.  Also, it is important to wait until you’ve had 3-4 warm days (50-55 degrees) to spray.  Your control will be very poor if you spray when the air temperature is too cold.  It may take 2-3 years of spraying to control the weed.  Many broadleaf herbicides will do a good job killing this weed.  The key is to kill it before it has a chance to bloom and set seed for new plants next year.  Call the Extension Office for recommendations of what and how much to spray on these weeds. 

There are many different weeds that could be present in your horse pasture.  They typically fall into 2 categories: broadleaf and grass weeds.  Grass weed control is limited (see paragraph below).  There are several options available to control broadleaf weeds - the buttercup mentioned above is just one such example of a broadleaf weed.  Call your local Extension office for assistance identifying weeds and determining the best and most cost effective herbicide to use.  

Due to label changes, there is now an option for controlling some annual grass weeds in perennial grass pasture.  Prowl H20 has been around awhile and was labeled for use in Bermuda grass pastures and hay fields.  A supplemental label is now available that allows for annual grass control in perennial cool season grasses like fescue and orchard grass.  It’s not a cheap herbicide so you will have to weigh whether the amount of weed present is worth the cost of the herbicide.  But it is certainly an option that may be useful in some situations. It is a pre-emergent herbicide; therefore, application should be made prior to germination.  Some grasses controlled include foxtails, goosegrass, shattercane, and signalgrass.  Here are some tips when using Prowl H20 in cool season grasses: 1) Temperature doesn’t matter, at least not as much as what we typically think.  So, February and March are good times to use this herbicide.  2) It breaks down quickly in anaerobic (no oxygen present) conditions.  So, don’t spray right after rain as the soil is saturated with water and there is no oxygen present in the soil.  Wait for the soil to dry out and then spray.  3) Use the high rate to get a good control.  This means about 4 quarts to the acre for best control.  This rate drives up the cost of application.  Finally, there are other herbicides with the same active ingredient but may have differing percentages.  According the labels, Prowl H20 is the only pendimethalin product that is labeled for use in cool season grass pastures and hay fields.  There are no harvest or grazing restrictions.  Temporary crop injury can occur, and application in extremely cold temperatures (and other conditions) may make crop injury more likely or more severe. 

Remember:  Always read and follow the label directions prior to using any chemicals.