Weeds

A weed is a plant growing where it is not wanted. Weeds are undesirable because they rob the desirable plants of nutrients and water, may reduce sunlight getting to the crop. may be a means of survival for pathogens and insects that infect or infest garden crops, and make work with the crop difficult.
Weeds reduce crop yield and the aesthetics of an ornamental garden.

Weeds can be divided into monocots and dicots. The monocot weeds are primarily grasses and sedges, characterized by their narrow leaves and parallel veins. Dicot weeds fall into many different families and characteristically have broad leaves and reticulate veins.