Weeds can invade your flowerbeds, vegetable garden and lawn areas. Some weeds serve a useful purpose, providing food for wildlife and protecting against wind and water erosion. What may seem like a weed to some people may appeal to other individuals. While some types of weeds may provide gardeners with attractive ground covers and native blossoms, others can take over entire yards, creating an unattractive landscape. Like many plants, weed plants fall into certain categories.
Some weed plants complete their entire life cycle in just one year. Known as annuals, these plants germinate from seeds, grow into mature specimens and produce new seeds for additional plants, then wilt and die, all within a single year. While summer annuals germinate in the spring and go to seed in the late summer or fall, winter annuals germinate in the fall and complete their cycle in the spring. Farmers who plant winter crops may struggle with winter weeds that compete with crops for water, sunlight and soil nutrients. Annual types of weeds include cocklebur, velvetleaf and foxtail. Mechanical methods, such as digging up and tilling the soil, can remove many types of annual weeds.
A versatile type of weeds, perennial weeds enter a dormant state in the winter and return the following spring. Perennial weeds may grow for many years, especially in areas where the soil remains undisturbed. Depending on the plant variety, perennials reproduce by seed formation, root division and vegetative cuttings. Perennial weed plants include broadleaf dock, tawny daylily and common comfrey. Although mechanical removal may reduce the appearance of perennial weeds, they may reappear from remaining root sections left in the soil. Stubborn varieties may require herbicides.
Biennial weeds complete their life cycles in two years. During the first year, these plants focus their energy on growing strong root systems and healthy foliage. They produce blossoms the second year that supply seeds for new plants. Biennial weeds grow in areas of minimal disturbance, such as along fencerows and between the rows of cultivated crops. Biennial plants include poison hemlock, wild parsnip and wild carrot. Herbicides and deep cultivation may help reduce the spread of biennial weed varieties.