Identifying Weeds
To make informed decisions, you will first need to correctly identify the various plants growing in your turf. Weeds are either narrow-leaved and grasslike or broad-leaved; the majority of weeds are broad-leaved. They also have varying life cycles that are important to know for you to effectively time your control measures. Annual weeds are the most common, living for one growing season and reproducing only from seed. Cool-season annual weeds germinate in late fall or winter; they then flower, produce seeds, and die in the spring. They can be especially troublesome in dormant southern lawns, and that is why some people overseed with cool-season grass for the winter. Warm-season annuals go through their complete life cycle from the spring to the fall of the same year. These weeds are most problematic in northern grasses that go dormant in the heat of summer. The important point to remember about all annuals is, because they reproduce only by seed, they can be controlled by disrupting their growth any time before they set seed.

Perennial weeds are the long-lived ones. They don't die after flowering, and many reproduce both by seed and by vegetative means such as rooting rhizomes. Some perennial weeds, like dandelions, have fleshy taproots that can produce a new plant from just a piece of root left in the ground. Creeping weeds, such as ground ivy, spread from underground rhizomes and above-ground stolons. Perennials are more difficult to get rid of, but they are as vulnerable during their seedling stage as the annuals.