Perhaps the best place to begin a lecture on weed control in forages would be to simply define the term "weed." It should be understood from the start that this term is one with several possible definitions. The table below summarizes several commonly accepted definition of the term weeds.

A weed is .....Weed

  • A plant out of place.
  • A plant that interferes with human activities.
  • A plant whose negative characteristics outweight its positive characteristics.
  • A plant whose positive characteristics have not yet been discovered.

While individual weeds vary greatly in their structure and function, weeds as a group tend to have a number of biological characteristics that make them very good competitors against forage crops. In the table below is a list of biological characteristics that enable weeds (and other plants that possess them) to spread rapidly into cropland and pastures. It should be understood that no one weed is likely to possess all of the characteritics below. Only one or two of these types of biological characteristics makes a weed competitive.

Biological Characteristics of Weeds

  • Produces large numbers of seeds
  • Is able to reproduce vegetatively via stolons or rhizomes
  • Seeds are able to remain dormant, but still viable in the soil for long periods of time.
  • Seeds have specialized structures for transport, for example burrs to cling to animals.
  • Exhibits allelopathic properties (Produces chemicals that inhibit the growth of other plants).