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How to Kill Sedge Grass

By Laura Wallace Henderson ; Updated September 21, 2017
Sedge grass in an aggressive type of weed.
sedge background image by Sergey Kolesnikov from Fotolia.com

Although commonly referred to as sedge grass, sedge actually is a weed that closely resembles several types of lawn grasses, and encompasses many varieties of invasive plants often mistakenly identified as grass. This aggressive groundcover poses problems for many homeowners and gardeners: Invasive tubers choke out areas of desirable grass species, often damaging large areas of landscapes. Killing sedge grass requires correct identification and eradication procedures.

Look closely at your lawn to determine the presence of sedge grass. Identify this type of weed by looking for patches of grass that grow quicker than surrounding areas, often reaching a few inches higher than the rest of the lawn.

Pluck a blade of grass from one of these patches, and roll it between your fingers and thumb to feel for obvious edges. Sedge stems form a triangular shape, compared to the rounded shape found in blades of lawn grasses. Pluck a piece of grass from a different area of your lawn and roll it between your fingers. True grass blades roll easily between your thumb and finger, due to their rounded shape.

Mow your grass before the sedge grass develops seed heads. This rapidly growing weed spreads rapidly through seed distribution. Cut your lawn as soon as you notice the presence of sedge grass.

Purchase a selective herbicide formulated to kill sedge in your type of grass. Treat your entire lawn as soon as you notice the presence of sedge grass. Avoid using a broad-spectrum herbicide, which may damage the desirable grass. Apply the herbicide according to the manufacturer’s instructions.

Apply fertilizer once the sedge grass is dead to make your grass strong enough to fight off invasive weeds, including sedge grass. Purchase a combination fertilizer and weed-killer to keep down the sedge and other weeds while strengthening your lawn grass.

Apply a pre-emergent herbicide to your lawn every spring before your lawn breaks its dormant cycle to eliminate the new growth of sedge grass. Select a variety intended for use with your type of lawn grass. Make this a regular practice to destroy sedge seeds before sprouting occurs.


Things You Will Need

  • Lawnmower
  • Selective herbicide
  • Fertilizer
  • Pre-emergent herbicide


  • Apply only herbicides listed as safe for your type of lawn grass. Do not allow herbicides to come into contact with nearby flowers and shrubs.

About the Author


Laura Wallace Henderson, a professional freelance writer, began writing in 1989. Her articles appear online at Biz Mojo, Walden University and various other websites. She has served as the co-editor for "Kansas Women: Focus on Health." She continues to empower and encourage women everywhere by promoting health, career growth and business management skills.