Common annual grass weeds include the crabgrass, foxtails, barnyardgrass, goosegrass and some biotypes of annual bluegrass. A wide variety of annual broadleaf weeds are often found in turfgrass areas. Biennial weeds require two years to complete their life cycle. The first year the weeds grow leaves and roots and store energy reserves. The second year flowers and seeds are produced and the plant dies.
Wild carrot is the most common biennial broadleaf weed found in turfgrass areas.
Perennial weeds live for more than two years and may persist indefinitely. Examples of perennial weeds include quackgrass, nimblewill, nutsedge, dandelion, white clover, etc. The incidence of weed invasions can be greatly reduced if a dense turfgrass canopy is maintained that provides continual competition to the seedling weeds. Therefore, it is important to select the proper species and cultivars of turfgrass for the site to be established. Once the turfgrass seeds germinate and the seedlings develop into established turfgrass, proper culture can have a major role in governing the weed pressures that ultimately develop.