Weeds compete for water, nutrients and light resulting in reduced flower yield and increased threat of serious insect and disease problems. A successful weed management program utilizes cultural practices such as cultivation and mulching, or a combination of cultural and chemical measures, taking into consideration labor costs and the cost and availability of materials. Weed management begins with a survey of the site. Weeds should be identified and the level of weed pressure noted. Weeds can be classified according to their life cycles.
Summer annuals emerge in the spring, flower, and set seed before the first frost.
In cultivated fields, summer annuals tend to predominate as the primary weed type. Winter annuals germinate at the end of the summer and overwinter as small, dormant, green plants. Biennials need at least two seasons to complete their life cycle and, like annuals, biennials die after flowering. Perennials which survive more than two seasons can propagate by seed or vegetative reproduction. Knowing the weed life cycle is important in determining the optimal timing of a herbicide application or cultural practice.