Lawn Weed Guide


Broadleaf weeds are a highly variable group of plants but most have showy flowers and net-like veins in their leaves. They are easy to separate from grasses due to their generally different leaf structure and habits of growth. Their presence causes a visual change in the over texture of the turfgrass in that area. Most of this group are summer annual broadleaf weeds.



1. Mow at The Proper Height

You can discourage crabgrass by mowing at the proper height for your grass type. Higher mowing, usually at one of the top two setting on your mower, encourages lawn grasses to shade soil which helps prevent the germination of crabgrass seeds. A thick, full lawn seldom contains much crabgrass.

2. Deep Water Your Lawn

Weeds are better adapted to adverse growing conditions than most lawn grasses. Shallow and infrequent watering will only weaken the roots of your grass, while allowing the crabgrass to thrive and take over. Water lawns deeply and less frequently. When you water, wet the soil to a depth of 4-6 inches. This usually requires 2-3 times watering per week in hot summer months.


How To Control Grass Weeds

Grass weeds in turf include crabgrass, goosegrass, crowfootgrass, sandburand annual bluegrass. These weeds are annual grasses which complete their life-cycles in less than one year. Annual bluegrass is a winter annual and the others are summer annuals. Torpedograss, a familiar grass weed of many turf areas, is representative of a perennial grass.


There are good sedges and bad sedges. Sedge lawn weeds are invasive in other types of turf grass. Controlling sedge weeds can be a challenge to many homeowners.

Sedge lawn weeds favor moist areas and are often naturally established in marshy areas or run-off zones. Controlling sedge weeds begins with an examination of your irrigation system and fixing low areas where moisture pools.

The first step is identification, as many types of sedge weed control are specific and there are more than 12 varieties of problem sedge.

These are some of the more common sedge weeds found in lawns:

  • Yellow Nut Sedge
  • Purple Nut Sedge
  • Annual Sedge, Watergrass
  • Cylindric Sedge
  • Globe Sedge

How To Control Sedge Weeds

Most sedges are well controlled by frequent mowing to remove the seed heads and prevent spreading. In the event that you have a widespread problem, you will have to resort to herbicide sedge weed control.

You need to fix any area of your irrigation system that releases too much water. You also can raise the soil level in spots with dips that collect moisture. Ensure that the soil has adequate percolation or drainage. Often this means removing entire areas of sod and mixing in compost, sand or other amendments that increase the porosity of the soil so excess water can drain down into the ground.