What is an Annual?
The term annual is applied to plants that complete their entire life cycle in one growing season. This means that they germinate in the spring, grow, flower, mature and set seed, then die in the fall.
There are many tender perennials grown as annuals in northern climates. They behave as perennials when grown far enough south that they are not killed off by frost in the fall. This group includes such plants as coleus, geranium, impatiens, lantana, and vinca. If one wants to save these plants from year to year, they need to be potted up, and grown-on indoors, or driven into dormancy and stored in cool, dark conditions. Cuttings can be taken from dormant plants in the early spring, rooted, and then transplanted after the risk of frost has passed.
There is also a group of annuals that appear to act as perennials because of the large amount of seed produced in the fall. The seeds germinate in and around the area where the heavy seeding annual was planted the previous season. Examples include amaranth, cleome, cosmos, pansy, and snapdragon.