Good weed management practices for a lawn and garden start with proper identification. Weeds come in broadleaf and grassy varieties as well as woody and vine types. Identification requires looking at characteristics such as size of the leaf or blade, flowers, growth habit, plant size and appearance of seeds or roots. Maintaining a healthy, dense turf reduces weed development, but most homeowners must use more direct control methods at some time.
Examine the leaves, stems and blades to determine the weed type. Grasses develop only one seed leaf and exhibit hollow stems. Examples include annual bluegrass and crabgrass. Broadleaf weeds, such as chickweed, ivy and dandelions, have two seed leaves at germination. Their leaves show a network of fine leaves. Most broadleaf weeds develop flowers as well. Vine-type weeds, including morning glory and bindweed, are easily identified by their long, trailing or twining growth habit, regardless of leaf appearance.
Learn the common weeds of your area. Not all weeds grow in all regions, which helps to narrow the possibilities. For example, bermudagrass and dallisgrass grow throughout the southern half of the United States, while Canada thistle contains itself to the northern states. Nimblewill is a grassy weed that grows as a native plant in the eastern United States.
Consider the dimensions of the weeds. Some weeds, such as crabgrass and henbit, remain low to the ground. Others, such as dallisgrass and black medic, reach from 6 inches to more than 2 feet above the ground. Note leaf width and thickness as well, which easily identifies some weeds. For example, yarrow has wide, thin, featherlike foliage while purslane has rounded, thick leaves.
Look at the flowers of blooming weeds. Both bindweed and morning glory develop small flowers, with those of bindweed reaching up to 1 inch in diameter and developing in pink and white colors. Wild buckwheat, another vine weed, is a summer annual that develops small white flowers from green buds. Dandelions develop fluffy, yellow flowers that later turn white, blowing off and spreading in wind. Other weeds that produce yellow flowers include hop clover and black medic. Chickweed, white clover and mallow all produce white blooms.
Examine pulled weeds' root structure. Weeds such as quackgrass and bermudagrass spread through rhizomes. Others, including curly dock, dandelion and plantain, have a large taproot. Shovel rhizome-spreading weeds from the ground, carefully removing the roots as well. Grasp taproot weeds at the base near the ground and pull them out, checking for the intact root. Water extremely dry areas three to four hours before weeding to improve weed root removal.
Use weed identification for clues regarding better lawn care practices. For example, crabgrass often develops in excessively watered lawns that are mowed very short.
Take a weed sample to your county Extension office for identification if necessary.