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How do I Identify the Common Lawn Weed?

By Cleveland Van Cecil
Weeds are plants not meant to grow in the area.
Backlit Weeds image by Jim Mills from Fotolia.com

You've likely seen them popping out of the turf like a sore thumb. Weeds. Common lawn weeds are broken down into two main classes: broadleaf and grassy weeds. Grassy weeds might look a lot like the turf you are trying to grow. Broadleaf weeds have larger leaves that spread out broadly. Weed identification is necessary for proper control. Some weeds may be difficult to identify on your own. If you are at wit's end, send a sample of your weed to your local university extension service to have it identified.

Broadleaf Weeds

Contact your local university extension service for a copy of your local weed identification key. The pictures provided will make identification easier.

Inspect the growth habit of the weed. Dig up the weed using a small shovel or hand trowel to inspect the roots. Spreading weeds will have roots that grow downward and connect underground using rhizomes. Clumping weeds will have several weed plants clumped together sharing a single set of roots. Upright weeds will grow as a one plant with a single set of roots.

Inspect the shape of the leaf. Look at the edge of the leaf for a serrated edge or thorns. Note the veins of the leaf to distinguish it from other broadleaf weeds. Compare the size of a mature leaf to the identification key.

Look at the leaf arrangement. Broadleaf weeds will have an opposite orientation, alternating orientation, whorled orientation or a trifoliate orientation (such as a clover).

Inspect the weed for any flowers. Note the shape and color of the flower and compare it to the chart.

Grassy Weeds

Inspect the grass blade for the vernation of the blade. The vernation is how the grass grows. Grassy weeds are either folded or rolled. Cut the grass blade using sharp scissors and inspect the vernation. Inspect the blade for any hairs at this time. Look at the shape of the blade end. Leaves are either sword-shaped, tapered or boat-shaped.

Inspect the projection at the base of the leaf blade to find the ligule. Look for a membrane, hairs or a naked ligule to find the grass type and compare it to your key.

Look inside the ligule for the auricle at the ligule base. The auricle will be lobed like an ear, clasping or absent.


Things You Will Need

  • Weed identification key
  • Hand trowel
  • Scissors