A perennial may be defined as a plant that lasts for 3 years or longer in a given locality. However, certain plants can be annuals, biennials, or perennials depending on the locality or purpose for which they are grown. These plants normally die down to the ground each winter and then renew themselves in the springtime and flower during the growing season. But some perennials such as the evergreen daylilies keep their foliage in winter.
Perennials are popular because they live for many years once established in the flower garden.
To plan a new perennial garden or to improve one that is in existence, you should first find out as much as you can about garden plants and their culture. You can learn a lot from reading popular gardening magazines, library books, and newspaper articles dealing with current gardening problems. For detailed information you can turn to books, periodicals, or the Home and Garden Bulletins of the U.S. Department of Agriculture dealing with specific plants. Other good sources of information are your fellow gardeners, members of garden societies, the county extension agents, State and Federal experiment stations, and commercial nurseries. Your perennial garden should be planned to satisfy your individual tastes and objectives.