Weeds, or plants out of place can become troublesome to turfgrass managers, and homeowners alike. Broadleaf weeds can be easily controlled, and sometimes serve as indicators of unusual conditions in the turfgrass environment. Some examples of this are:
- Low pH - sheep sorrel
- High pH - broadleaf plantain
- Compaction - goosegrass
- Low Nitrogen fertility - legumes (clover)
- Poor soil - quackgrass
- Poor drainage, moist soil - sedges
- Surface moisture - algae
Broadleaf weed control involves management practices that encourage the most favorable conditions for the desired plant species (your grass) that will make it the most competitive it can be. Maintaining a dense stand of turf will reduce all weed problems because the weeds need space, and in most instances light, to germinate in your turf. The existence of weeds in a stand of turfgrass indicates a lack of turf health and vigor and the existence of voids, or empty spaces. Voids can appear in your turf due to natural causes like environmental stress, flooding, excessive use of an area(traffic, divots), diseases, and insect damage or by management practices like improper mowing height, improper fertilization, improper irrigation, insufficient drainage, and excess thatch. Weeds usually appear in the empty areas of turf and become more of a problem as more voids occur. If broadleaf weed problems do occur, there are many cultural and chemical means available to control the situation. The steps you need to take in controlling a weed infestation are:
- Identify the weed in question.
- Why is the weed there ? Does it indicate something about the turf environment ?
- Modify the environment using cultural methods.
- Use appropriate herbicide for control.
Chemical control of broadleaf weeds is primarily done postemergence, although a few broadleaf weeds are controlled by a preemergence application of herbicide. Since the introduction of 2,4-D in 1944, chemical control of broadleaf weeds has become more refined and in most cases, easier.