Managing Weeds in CREP Grasslands

It's time to think about managing those weedy plants in CREP before they set seed.
Managing Weeds in CREP Grasslands - Articles


We routinely receive questions about weed management in CREP grasslands. Unfortunately, when it comes to CREP, there is not just one answer that can be given when providing a weed control recommendations. In general, mechanical and chemical means are typically used, however, certain guidelines established in the CREP contract must be followed in order to remain in compliance. Certain deviations may possibly be made but only after consulting with an FSA advisor. Below are some things to consider when dealing with weeds in your CREP acres.

Mechanical Management--Mowing and Hand Removal

  • Annual mowing of the entire CREP area is not allowed after the stand is established.
  • Mowing may be used as necessary during the establishment period (first one to three years).
  • After the establishment period, mowing is not allowed from April 1 to July 31.
  • Spot mowing for weed control from April 1 to July 31 must be approved in advance by the Farm Service Agency. Only spot mowing may be approved.
  • Approved mowing may occur from August 1 to August 31, but no more than one-third of the area may be mowed in most CREP contracts.
  • If you see a new weed, dig it, pull it, or remove the seed head prior to seed dispersal.
  • Herbicides may be a better alternative than mowing for problem weed control.

Chemical Management--Herbicides

  • In CREP areas, herbicides are an effective means to control unwanted vegetation.
  • Spray biennial weeds in the rosette stage before they overwinter or prior to bolting in the spring. Biennial rosettes are most susceptible to herbicides prior to overwintering.
  • Perennials are most susceptible to control with systemic herbicides in the bud to bloom stage or in late summer/early fall; spring herbicide applications usually provide ineffective control.
  • A single herbicide application will not eradicate a perennial weed problem; therefore, long-term, routine maintenance tactics are required for management.
  • In CREP areas, spot spraying with a backpack or handheld sprayer is usually the best and most economical method for scattered weed infestations.
  • Weeds tolerant of the herbicide may invade the space left by susceptible species, ultimately creating a more severe weed problem.
  • Most herbicides labeled for use on CREP grasslands may cause injury or kill many kinds of broadleaf plants including legumes. Refer to the herbicide labels for additional details.
  • Herbicides such as 2,4-D, Clarity, Crossbow, Cimarron (metsulfuron), ForeFront, Redeem R&P, and glyphosate (spot-applications) among others, are typically used to control broadleaf weeds in established CREP grasses.

For more detailed information about weed management in CREP grasslands, refer to the " Weed Management in CREP Grasslands " fact sheet. Refer to the section titled "Herbicides for Use in CREP Grassland Areas" and Table 2 at the end of this publication for more information on herbicides and their effectiveness on selected weed species.