MSUcares Extension Header Return to MSUcares Home Page

Weed-Control Calendar for Warm-Season Turfgrasses

Information provided in this publication is targeted for areas around Starkville, Mississippi. In the Jackson area, move dates back about 2 weeks; near the coast about 3 weeks; and north of Starkville near Hernando or Corinth, move the date forward about 2 weeks.

February-April

Fertilizer

Proper fertilization helps turfgrass compete with weeds. Apply fertilizer as soon as the danger of frost is past. Refer to Extension Publication 1322, Establish and Manage Your Home Lawn, for more specific information. Generally, 1 pound of actual nitrogen per 1,000 square feet (ft2) is recommended to provide adequate nitrogen for turfgrass to start growing. However, the fertilizer should also contain enough potassium to ensure good root growth and development.

Mowing

Mowing is an easy way to remove unsightly weed growth in the lawn. The first time you mow your lawn each spring, set the mower at the lowest possible setting but not low enough to scalp the turf. The primary purpose of low mowing is to remove those dead turfgrass leaves and stems and winter weeds so the newly emerging turfgrass is not shaded. Close mowing also permits more sunlight to reach the soil surface and helps warm the soil. While this creates a favorable environment for turf growth, it also creates an environment suitable for weed emergence. You should do this treatment before turfgrass green-up.

After the initial low mowing, mow as needed to the recommended mowing height, remembering to mow frequently enough that not more than one-third of the plant material is removed each time.

Burning

Although you cannot use burning inside most city limits, you can burn to remove dead turfgrass leaves and stems (thatch) and weeds from the lawn. If you decide to use burning, you should do so before any signs of green up to avoid damaging the turf. Heat generated by burning may help stimulate turfgrass emergence, resulting in more rapid green up of the lawn. Burning can be a dangerous method of weed control even if you use extreme caution. Wind conditions can shift, creating a situation that can damage ornamentals, structures on the property, or structures on adjacent property. Always be careful using fire as a method of weed control.

Hand Weeding

If your lawn has only a few weeds, you may choose to remove them by hand rather than apply a herbicide solution. Remember to remove the entire plant, including the root system, to avoid regrowth.

Preemergence Herbicides

Apply a preemergence herbicide by March 1 to prevent weeds from emerging. Apply the preemergence herbicide and water it into the soil before weed seed begin to germinate. Numerous preemergence herbicides and weed and feed products contain both fertilizer and a preemergence herbicide that can be used on warm-season turfgrasses. Refer to Extension Publication 1744, Weed Control in Home Lawns, for a list of products, but remember to read the product label and make sure it can be safely used on the turf in your lawn.

If you use a weed and feed product or granular herbicide formulation, you may choose to apply one-half the recommended rate in one direction and the other half perpendicular to the initial application. Generally, a preferred preemergence product contains one of the dinitroaniline herbicides (benefin, oryzalin, pendimethalin, or prodiamine), dithiopyr, or metolachlor.

You may take one of two approaches for spring preemergence herbicide applications. Crabgrass seeds start to germinate when soil temperatures reach around 55 °F, but goosegrass seeds don't germinate until soil temperatures reach about 65 °F. Therefore, many professional turfgrass managers prefer to split the spring preemergence herbicide application with one-half the recommended rate applied by March 1 and the other half applied in early May. This strategy provides the highest level of control for these troublesome grassy weeds.

Postemergence Herbicides

You can use postemergence herbicides to control winter broadleaf weeds that escaped earlier treatments and mowings as well as summer broadleaf weeds that have emerged. A three-way mixture of the following ingredients is preferred for postemergence applications: 2,4-D, MCPP, MCPA, mecoprop, or dicamba. Many brand names are available at lawn and garden centers, agrichemical dealers, hardware stores, and other sites. The concentration of ingredients varies by brand, as do the types of turfgrass on the product label, so use caution when purchasing. Apply these herbicides before turfgrasses start to green up for summer growth. To avoid injury, be sure to keep the herbicides away from ornamentals and flowers.

May-July

Fertilizer

Apply fertilizer according to soil test report.

Mowing

Mow as needed to the recommended mowing height, remembering to mow frequently enough that not more than one-third of the turf vegetation is removed each time.

Hand weeding

If you choose to remove weeds by hand rather than apply a herbicide solution, remember to remove the entire plant, including the root system, to avoid regrowth.

Preemergence herbicides

If you split the spring application, apply the second half of the recommended rate.

Postemergence herbicides

If annual grasses, such as crabgrass, or perennial grasses, such as dallisgrass have emerged, apply a postemergence grass herbicide. In bermudagrass or zoysiagrass lawns, MSMA is the preferred treatment. Make two applications for larger annual grasses. Three applications may be necessary to control perennial grasses. Apply 14 to 21 days apart. If you have a centipedegrass lawn, apply Vantage for postemergence grass control. There are no postemergence herbicides to control grasses in St. Augustinegrass lawns.

Apply the three-way mixtures (see previous paragraph on postemergence herbicide under February-April section) to control emerged, small, actively growing broadleaf weeds.

August-October

Fertilizer

Apply fertilizer according to a soil test report. Be sure to apply a fertilizer high in phosphorous and potassium to provide protection against winter damage.

Mowing

Continue to mow as needed to the recommended mowing height, remembering to mow frequently enough that not more than one-third of the plant material is removed each time.

Hand weeding

If removing weeds by hand, remember to remove the entire plant, including the root system, to avoid regrowth.

Postemergence Herbicides

Continue to treat perennial grasses with MSMA. If nutsedge has been identified as a problem weed, use Manage or Image for control. Use a three-way herbicide mixture, as previously discussed, to control remaining broadleaf weeds. Watch carefully for wild garlic emergence. The three-way mixtures provide excellent control of wild garlic, if applied while the plants are small and actively growing. An alternative method to using a hand sprayer for herbicide application is to apply the three-way herbicide solution to wild garlic using a piece of carpet remnant soaked in herbicide solution. The synthetic fibers in the carpet may help remove the waxy covering on the garlic leaves and reduce the barrier to herbicide uptake.

Preemergence herbicides

Toward the end of this period is the time to make the fall preemergence application. Atrazine or simazine is the preferred herbicide for fall applications, but these herbicides can be damaging to shallow-rooted trees and ornamentals. Pendimethalin, benefin, oryzalin, prodiamine, and isoxaben will also control many winter weeds without damaging ornamentals and shrubs. If you use weed and feed combinations, the product should contain the appropriate balance of nitrogen (N), phosphorous (P), and potassium (K) for this time of year. Be careful with weed and feed combinations, since high rates of nitrogen late in the year can be harmful to warm-season turfgrasses.

November-January

Preemergence herbicides

See comments above.

Postemergence herbicides

Watch for wild garlic emergence. The three-way mixtures provide excellent control of wild garlic if applied while the plants are small and actively growing. An alternative method to hand spraying the three-way herbicide solution on wild garlic is using a piece of carpet remnant soaked in the herbicide solution to wipe the solution onto the garlic. The synthetic fibers in the carpet may help remove the waxy covering on the garlic leaves and reduce the barrier to herbicide uptake. Image also provides excellent control of wild garlic but should not be applied until after the first killing frost and before January 1. Roundup or Finale can be wiped onto leaves of individual clumps of wild garlic.

By John D. Byrd, Jr., Ph. D., Extension Weed Specialist, G. Euel Coats, Ph. D., Professor of Weed Science, and Steve Kelly, Research Associate II.

Mississippi State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status.

Publication 2171
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director

Copyright by Mississippi State University. All rights reserved.

This document may be copied and distributed for nonprofit educational purposes provided that credit is given to the Mississippi State University Extension Service.

A black line that separates the body text from footer information