Most gardeners know that flowers are primarily grown from seeds. However, what most gardeners do not know is that seeds are actually ripened or mature ovules of a plant. The seeds of a flower contain a fertilized embryo of a plant capable of germinating a new plant. Some plants produce large numbers of seeds and others only produce a few. Although there are some plants that can be started from bulbs, corms or cuttings instead of seeds, most plants begin as seeds. In addition, seeds have distinct classifications depending on the type of plant they produce and its overall production rate and life cycle.
Most nursery bedding plants are grown from annual seeds. Annuals only live through one growing season. These types of plants must be grown from seed each year. Although annuals must be planted each spring, they are popular due to their brilliant colors and many varieties. Common annuals include impatiens, pansies, petunias, and zinnia. However, in climates that are warm and dry, the seeds that fall from these plants may survive the winter and grow in the spring. When that happens, the plants are called self-seeding.
Perennial plants have a long life cycle and will grow year after year from the same roots. A majority of landscaping plants such as the hosta, edging foliage plants and most ferns are perennials, as are herbs such as chives, lavender, sage and Echinacea. Many flowers are perennials, and as such should be planted as seeds only if you want the same flowers to appear in the same spot year after year. Black eyed-Susans, daisies, and coneflowers are all examples of perennial flowers that can be grown from seed.
Biennials produce flowers during their second season. These plants generally die after their flowering season. They develop leaves and a root system the first year and blossom early in the spring of the second year. According to Organic Gardening, some old-fashioned biennials such as hollyhock, fox glove and sweet William are hardy self-seeders that ensure regeneration of the flowers.