Botanists and horticulturists classify flowering plants in a number of different ways: based on the plant's growth habits, how long it lives, how it reproduces and whether it survives the cold or not. Every continent, with the exception of Antarctica, boasts flowering plants able to thrive in habitats as cozy as the tropics to the chill of a subalpine forest. Flowers range in size from microscopic, in the case of the smallest orchids, to huge peonies as large as a dinner plate.
These flowers complete their life cycle in one season. They germinate, grow to maturity, flower, set seed and die. Alyssum, Cosmos and Zinnias are annual flowers.
Biennials sprout the first year and grow to maturity, then go dormant in the fall. The second year the plant grows leaves again, flowers, sets seeds and dies. Hollyhocks, Digitalis and Queen Anne's lace are biennials.
Bulbs have many layers attached to a basal plate. The flower-to-be is in its embryonic state within the bulb. If growing conditions are right the bulbs will flower every year. Some bulbs like daffodils and tulips require a chilling period, while others like amaryllis will not live through cold winters.
Corms are similar to bulbs in that the genetic material to reproduce the plant is inside them. There are no layers within the bulb. Corms include freesias and gladiolus.
Hardy flowers will survive cold winters. Some flowers like Siberian Iris are hardy to zone 2 while others like roses are only hardy to zone 4 and still others won't tolerate frost so aren't hardy below zone 9.
Most flowers bloom during the day, but there are some that bloom at night such as tropical water lilies and angel's trumpets and others like four o'clocks that bloom shortly after sunrise and right before and after sunset.
Perennials live for several years. Some peony plants have lived for more than 20 years. Perennials sprout the first year and expend all their energy into growing without flowering. The second year there is more growth both of the bush and the root system. There may a few flowers. After the third year perennials flower consistently. Roses are perennials as are chrysanthemums and carnations.
Tubers are the reproductive method of several flowers such as dahlias and begonias. The tuber itself is alive and must be kept where it won't dry out or it won't sprout.
Tropical flowers do not tolerate frost and some, such as orchids, won't tolerate temperatures lower than 50 degrees Fahrenheit.