Pests in Gardens and Landscapes: Quick Tips

Weeds in Lawns

Published   4/24

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Smooth crabgrass growing in a bermudagrass lawn.

Smooth crabgrass growing in a bermudagrass lawn.

Broadleaf plantain.

Broadleaf plantain.

Flowering dandelion.

Flowering dandelion.

Weeds can occur in all lawns but rarely become problems in well-managed, healthy turfgrass. Poor maintenance practices—such as improper fertilization, watering, and mowing—can weaken turfgrass and make it susceptible to weed invasion. Total eradication of weeds isn’t realistic or necessary for most lawns. With good management practices, a lawn can be vigorous and attractive with little or no herbicide use.

Why is weed identification important?

  • Different weeds may require different management approaches.
  • Many weed species are associated with lawn conditions, such as overwatering, compacted soil, or low fertility. Identifying the weed species can give an indication of the underlying lawn care problem, which can be corrected.
  • For help identifying weeds, visit ipm.ucanr.edu.

Prevent weed invasions with proper lawn care.

  • Choose a turfgrass species well adapted for your area or needs.
  • Uniform water coverage is essential; regularly check sprinkler heads and adjust if needed.
  • Water deeply and infrequently.
  • When mowing, remove no more than one-third of the leaf blade. Mowing height can vary depending on turfgrass species.
  • Fertilize with 1 pound of actual nitrogen per 1,000 square feet per application up to 4 times a year.
  • Heavy traffic can compact soil; aerate the soil when grass is actively growing.
  • Remove thatch if it is more than half an inch thick.

When weeds invade:

  • Identify the weed species.
  • Determine if there is an underlying lawn care problem such as improper fertilizing, watering, and mowing, and correct it.
  • Remove weeds by hand when they are young and before they flower, set seed, form vegetative parts, or spread into patches.
  • Overseed, patch, or renovate problem areas within the lawn.
  • Before using an herbicide, address the underlying reason why weeds are invading.

What about pesticides?

  • Choose a selective herbicide that is labeled for use against your problem weed and can be used without damaging your turfgrass species.
  • Nonselective herbicides can harm desirable turfgrass and other plants.
  • Contact herbicides damage plant tissue but don't kill plant roots. These herbicides are most successful when applied to young weeds.
  • For more information on herbicides available for use on lawns, see the UC IPM Pest Notes: Weed Management in Lawns.

Minimize the use of pesticides that pollute our waterways. Use nonchemical alternatives or less toxic pesticide products whenever possible. Read product labels carefully and follow instructions on proper use, storage, and disposal.


Statewide IPM Program, Agriculture and Natural Resources, University of California
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