Summer annuals germinate in the spring, mature in the summer, and die in the fall. The seeds remain dormant until the spring. Annual weeds characteristically produce a great number of seeds. These seeds have the ability to become established in a wide range of environments and to remain viable over an extended period of time. Control of annual weeds, for the most part, is dependent upon the control of the seeds.
Biennial weeds reproduce by seed and live for two growing seasons.
They sprout and undergo vegetative growth during the first season, then flower, set seed and die in the following season. Control of biennial weeds is centered on control of the plant in the first growing season before it has a chance to set seed. Perennial weeds reproduce both by seed and vegetatively. They produce new top growth from buds located on the root stock. The root stock can be bulbs, tubers, rhizomes, stolons, crowns or taproots.