Hairy Buttercup (fig.1) and Buckhorn plantain (fig. 2) are weeds we often get calls about whenever it is too late to for herbicides to be effective. For example, once you see the “sea of yellow” in the spring time, it is too late to spray for hairy buttercup. We have two opportunities to spray for these weeds: October to mid-December and March to early April when there has been at least three days of 60 F or higher temperatures so the herbicides can be the most effective.
Historically, herbicide recommendations for both weeds would include 2,4-D ester or products containing aminopyralids + 2,4-D (GrazonNext HL), picloram + 2,4-D (Grazon P+D), or dicamba + 2,4-D (Brash, Weedmaster, Range Star).
While those recommendations are still good, there is a new herbicide available that provides excellent control of buckhorn plantain, buttercups, and other difficult-to-control weeds such as wild carrot and poison hemlock, and that is DuraCor by Corteva. Dr. Neil Rhodes, UT Extension Weed Specialist, states UT studies show that a rate of 12 oz per acre of DuraCor with a standard rate of surfactant will provide excellent control of buckhorn plantain and buttercups when applied at the proper time. DuraCor has been included in our 2021 Weed Control Manual (Publication 1580) for a variety of weeds, including buckhorn plantain and buttercups. You can pick up a copy from our office at no charge.
DuraCor contains the active ingredient aminopryralid, but it also contains the first new active ingredient for broadleaf weed control in over 15 years, which is Rinskor active. Since it is not restricted, you can purchase this product without being a certified private or commercial applicator. The low use rate makes it an affordable option for producers.
There are no grazing restrictions for livestock, but there are stewardship guidelines to follow regarding hay and manure, which are the same as that of GrazonNext HL. Be sure to read and follow the entire label of DuraCor or any other herbicide. DuraCor will unfortunately kill legumes and should not be applied where the loss of legumes cannot be tolerated.
If you are just needing to spray for hairy buttercup only, 2,4-D ester will provide excellent control. An application rate of two pints per acre in at least 20 gallons of water per acre is recommended. This rate will kill all red clover, but will spare most established white clover. It is not recommended to apply this herbicide if you have recently seeded in legumes. If you have, you will need to wait until October-Mid December to make your applications. DuraCor has a longer residual than 2,4-D. If you apply DuraCor, you will need to wait approximately one year before you can successfully reseed clover.
As always, please remember to read and follow the label of any herbicide you use.