Weeds are probably the most serious and frustrating pest problem in most landscapes. A weed is generally described as a plant out of place. Weeds are the optimists of the plant world, ready to take advantage of any failure of the maintenance program.
In weed control, there are two factors to realize. First, weed seeds are in most soils. Second, a weed seed can live in a soil for years waiting for a chance to germinate.
In developing a control program, establish a plan that produces a thick, dense turf. Weeds have a difficult time invading a high quality turf.
Weeds, once established, can be controlled mechanically or by use of chemicals (post-emergent's). To remove mechanically involves digging up all the above and underground parts of the weed capable of growing a new plant, such as rhizomes. If all parts are not completely removed, the weed will simply re-establish itself in a short period of time.
When considering using chemical control, remember a chemical toxic to the plant is being used to remove an undesirable plant (the weed) from a population of desirable plants (the turf). Sometimes this is difficult, especially if you are trying to remove a grass out of a grass. Most broadleaf weeds can be controlled with a herbicide. Always follow the label.
Another way to control weeds is through the use of pre-emergent's. This type of herbicide kills seeds as they germinate but has no effect on the growing plant. It gets its name from the fact that it kills weed seed plants before they emerge from the ground.
Understanding the growth and reproductive characteristics of a weed is the second most important step in developing a control strategy. Environmental and cultural practices that discourage weed infestations are important in producing an acceptable weed-free turf. Turf weakened by improper cultural practices (watering, mowing, and fertilizing) is more susceptible to weed invasion.
Herbicides are useful tools for the control of weeds but only provide short term relief.