Whether your lawn consists of a cool season or warm season turf, weeds can be a problem year round. Controlling weeds is made easier when you know your turf type, the weeds to be controlled, and how and when to apply proper control measures.
Cool season weeds like henbit, chickweed, cudweed, annual bluegrass, vetch, clover and lawn burrweed are up and growing now. These weeds need to be controlled before they begin flowering.
If your lawn has been overtaken with weeds, a chemical spray may be required. Before applying any chemical make sure it is labeled as safe for use on your turf type and will control the problem weed. You don’t want to accidentally kill the grass when attacking the weeds.
Summer annual weeds like crabgrass, carpetweed, purslane, prickly lettuce, buckhorn plantain and spiny sowthistle are preparing to emerge in the next couple of months. Summer annual weeds can be controlled with a pre-emergence herbicide.
One of the most popular weeds to control this way is crabgrass. Late February to early March is when crabgrass seeds germinate, so application as soon as possible is recommended. Many other summer annuals will begin to germinate toward the end of April and into May. Read the directions carefully on the chemical you choose to determine if a second application is needed.
Many people ask about cultural methods for controlling weeds. Control methods that don’t cost a lot, can be easily implemented and minimize the use of chemicals. The first method is to mow the lawn at the proper height. A thick, healthy stand of tall fescue mowed at a height of three to four inches will prevent more than 90 percent of annual weed seeds from germinating. Pulling the other 10 percent can be counted as exercise, a great way to keep that resolution to loose a little weight.
A thick canopy of warm season grass will also keep weeds at bay, especially during the summer when the grass is growing most vigorously. A good rule to remember for keeping turf vigorous is to never remove more than 1/3 of the leaf blade at any one mowing. Removing more will shock the grass and give the weeds an opportunity to leap ahead.
Another cultural practice is to keep the grass healthy. A healthy grass is one receiving the proper amount of fertilizer, water, sunlight and growing in a soil with the proper pH.
A free soil test done by the North Carolina Department of Agriculture and Consumer Services Agronomic Services Division will provide the information needed to give the lawn the proper nutrition. Soil boxes and forms needed for the test can be obtained from the local office of NC Cooperative Extension.
A healthy lawn will not only help control the weed population, but also reduce the chance of disease in your lawn.
Extension Master Gardeners are a great resource for people needing help identifying their turfgrass or weed. They can be contacted through your local County Cooperative Extension Service. To locate your local extension office, go to www.ces.ncsu.edu.
The Turf Files website is a great place to find an identification key, management options, articles and up to date information. This website is great for both homeowners and turfgrass professionals and is available at www.turffiles.ncsu.edu.
Photos courtesy of NC Cooperative Extension Service.
Shawn Banks is the Consumer Horticulture Agent with the NC Cooperative Extension Service in Johnston County. You may reach him at firstname.lastname@example.org.