Weed Control Options for Newly Established Tall Fescue

Renovating a pasture takes guts. To hook up to a cutting harrow or sprayer full of glyphosate to kill green pastures and embark on a nerve-wracking journey is no easy feat. But when you make it to the end and see young tall fescue plants popping up, you likely have a great feeling of accomplishment. You should!  You overcame a million excuses not to renovate and actually put that thought into action.

So, if you made it to this point of young tall fescue plants emerging and developing, you might think you are at the last step of renovation. However, one critical step is left to ensure this young and quite expensive investment is successful for many years to come. Common weeds in newly established stands include biennial thistle, buttercup, henbit, dock, purple deadnettle, chickweed, etc. At heavy enough populations, any of these species can hinder a new stand from successful establishment. In many cases, broadleaf herbicide applications can control or suppress these annual weeds to shift the competitive advantage to the tall fescue. A few scenarios below provide guidance on herbicide options for specific situations.

Before applying a herbicide you will need to:

  1. Identify the weeds in question.  There are many web resources to help you with this, or you can ask an advisor for help in identification.
  2. Identify your forage’s growth stage (Figure 1). Applications before the V3 stage (tillering) may cause damage to the novel endophyte tall fescue seedlings.

Commonly used herbicides in newly established tall fescue include 2,4-D (4 lb.), WeedMaster (2,4-D + Dicamba), GrazonNext HL© (2,4-D + aminopyralid), and DuraCor© (Rinskor + aminopyralid). Control of biennial thistles (Plumeless, musk, etc.), buttercup, henbit, dock, purple deadnettle, chickweed varies among these herbicides, and one should consult their local extension agent for region specific recommendations. Below are 2 herbicide application scenarios that may fit for your operation, but should only be used as guidance and are not specific recommendations. Remember, as weeds mature, we generally have a tougher time achieving adequate control.

Scenario 1: Newly established tall fescue pasture that has heavy populations henbit, and chickweed and traditionally has issues with pigweed in the summer.

In this scenario, an application of Weedmaster 2 pt/ac + NIS 0.25% v/v for the current weed issue should provide adequate control. We would not make an application of GrazonNext HL or DuraCor at this time because we want to save that herbicide for our summer weed problem and stay within labeled rates. For the pigweed issue in the summer months, the producer can apply DuraCor 16 fl. oz./ac + NIS 0.25% v/v should provide adequate control.

Scenario 2. Newly established tall fescue pasture that has heavy population of Buttercup, Biennal thistles, and dock.

All species in this scenario are extremely sensitive to DuraCor and GrazonNext HL, so an application of DuraCor 16 fl. oz./ac + NIS 0.25% v/v or GrazonNext HL 24 fl. oz./ac + NIS 0.25% v/v should provide adequate control.

~ Sam Ingram, Corteva

The Alliance for Grassland Renewal is a national organization focused on enhancing the appropriate adoption of novel endophyte tall fescue technology through education, incentives, self-regulation and promotion.  For more resources or to learn more about the Alliance for Grassland Renewal, go to www.grasslandrenewal.org

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