How to Identify the Common Weeds in Your Garden

Grasses and Grasslike Weeds

• 1

  Note whether the grass or grasslike weed is growing in a clump or if it's spread out. Crabgrass (Digitaria spp.) and foxtails (Setaria spp.) are two examples of clumping grass weeds.

• 2

  Look at the collars and the ligules. The collar region is the junction between the sheath and the blade of grass; the ligule is the growth standing up from the collar. Ligules may be absent, hairy or membranous. Foxtails have hairy ligules. Creeping bentgrass (Agrostis stolonifera) has membranous ligules.

• 3

  Study the characteristics of the blades and sheaths of the grass weed. Characteristic features include hair, edges, midrib and color. Bermudagrass (Cynodon dactylon) has hairy leaf edges. Wild garlic (Alium vineale), a non-grass monocot, has leaves that are waxy.

Broadleaf Weeds

• 4

  Notice whether the leaves are arranged oppositely or alternately on the stem. Opposite leaves are directly across from each other; alternate leaves stair-step on the stem. Dandelions (Taraxacum officinale) and buckhorns (Plantago lanceolata) are examples of alternate-leaved weeds. Chickweed (Stellaria media) and ground ivy (Glechoma hederacea) are examples of opposite-leaved weeds.

• 5

  Note the shape of the leaf or any other distinguishing leaf characteristics. Dandelion leaves, for example, are deeply lobed and the lobes point backward toward the stem. Violet (Viola spp.) leaves are heart-shape. The leaves of ground ivy are scalloped and form a tight kidney shape. The leaves of Canada thistle (Cirsium arvense) are deeply lobed and spiny.

• 6

  Note any flower characteristics, as these can help you quickly identify broadleaf weeds that are in season. Violets have small, five-petaled, purple flowers. Purple loosestrife (Lythrum salicaria), once commonly sold at nurseries, has six-petaled purple flowers on stems that may reach 5 feet tall.