Weeds are common to all lawngrasses .
They increase the maintenance cost of a lawn, reduce the land value and in some cases contribute to allergies and poisonings. Weeds compete with all desirable plants for water, nutrients and sunlight. They also harbor insects and diseases that might attack lawngrasses, trees and shrubs. Lawns which are properly maintained are less apt to be plagued with weeds. A vigorously growing lawn provides little area for weed seed to germinate and will usually smother out those that do germinate.