Annual plants are one of the most popular types of plants for every gardener. Annuals have many advantages for the home gardener, including hardiness, low cost and some of the best blossoms around. Annuals come in every color of the rainbow, and in a variety of sizes and shapes as well. A properly planted garden of annuals is a breathtaking sight indeed.
What separates annuals from other types of plants and flowers is that they grow from seed, blossom, set seed and die to ground, all within one growing season. While some other types of flowers are treated as annuals and replaced each year, all true annuals share this important distinction.
Annuals are further divided into several categories – hardy, half-hardy and tender – according to their tolerance for cold temperatures. Pansies are a good example of hardy annuals, and they thrive in cool and even cold conditions. Hardy annuals are usually planted in the fall for color throughout the colder months. Most varieties of hardy annuals begin to decline in the spring, and die when the heat of summer begins to arrive.
Half hardy annuals, on the other hand, can tolerate a light frost but not a hard one, and they are generally planted early in springtime to provide color throughout the spring and early summer. Half hardy annuals, like dianthus, generally start their decline in the heat of the summer, but they can bloom again the autumn.
Tender annuals, on the other hand, cannot tolerate any freezing temperatures at all. Tender annuals, such as zinnias, impatiens and vincas, should not be planted until any danger of frost is gone.
Annuals are most often used as landscape plants, and the colors and varieties of annuals make them ideal for use in the landscape. It is important to remember that most annuals need full sunlight for at least four to six hours every day in order to produce the best blooms. There are, however, shade tolerant varieties of annuals, such as impatiens, coleus and begonias, and they can be used in parts of the landscape that receive less sunlight.
When selecting planting locations for annuals, it is best to avoid areas where water pools after heavy rain. Pooling water can drown the roots of many annuals. It is also important to avoid planting annuals in areas that are close to trees or large shrubs, since the root structures of these large plants can compete for moisture and leave your annuals without sufficient water.
It is also important to prepare the planting bed properly to get the most from your annuals. The planting bed should be deeply spaded and dug between six and ten inches deep. Clay heavy soils should be amended prior to planting by mixing in at least two inches of humus, leaf mold, compost or small pea gravel. These improvements will help the soil drain well and provide additional aeration as well.
It is important as well to test the soil properly before planting annuals. Most varieties of annuals thrive in soil pH from 5.8 to 6.5, but more alkaline soils will need to be amended prior to planting.