What Kind of Weed Is Growing on My Lawn?

Broadleaf

• Broadleaf weeds typically have wider leaves than grassy weeds or sedges, according to Texas A&M University. If gardeners look at the broadleaf weed's leaves, they will notice that the leaf has a mid-vein. The other veins on the leaf will not run parallel to this mid-vein. Also, broadleaf weeds typically have more colorful flowers than grasses or sedges. Gardeners can remove broadleaf weeds from the lawn by using a post-emergent herbicide specifically formulated to kill these weeds. Avoid applying the herbicide when soil moisture is low or you could harm your turf, according to Purdue University.

Grass

• Grass has triangular tips, which are different from sedges or broad leaf weeds. A number of common grass weeds infest lawns such as annual bluegrass, crabgrass, bermudagrass and goose grass. Gardeners should check their soil to make sure it isn't compacted if they are plagued every year from grassy weed growth. Soil compaction, overwatering and low mowing can encourage grassy weed infestations. Apply a post-emergent selective herbicide to grassy weeds as you see them pop up during the growing season.

Sedges

• Sedges are commonly mistaken for grass, but they have rounded tips. Gardeners typically find themselves fighting off sedges such as nutsedge and green kyllinga, according to the University of California. You may see sedge growth in areas that have poor drainage. Use a post-emergent herbicide that contains halosulfuron to kill off sedges, as recommended by the University of California. Because post-emergent herbicide will only kill the above portion of the sedge, you may have to continually apply the spray for the underground roots to die off.

Pre-Emergent Herbicide

• There are a number of pre-emergent sprays that are formulated to prevent broadleaf, grass and sedge weed seeds from germinating. A soil thermometer comes in handy when figuring out when to apply these sprays before weed seed germinate. For instance, crabgrass seeds germinate when soil temperatures reach 60 degrees Fahrenheit in the spring. Check the soil temperature and apply pre-emergent spray before soil temperatures hit 60 degrees. Other pre-emergent sprays will indicate when they must be applied.