The classification of flowers is one section of the science of taxonomy, or the classification of organisms. This hierarchy of classification is based on processes of development, methods of propagation, growth and other characteristics shared by groups of organisms. The hierarchy proceeds from the most general to the most specific: kingdom (plants distinguished from animals); phylum (methods of development, like spores or seeds); class (generally whether plant seeds contain one or two leaf sprouts); order (further development information shared by groups of plants); family (plants with even stronger similar characteristics, like bromelia and pineapple); genus (all the varieties of pineapple); and species (often named for the discoverer). While not all botanists agree on exactly where plants belong in this hierarchy, sorting them is the first step in learning about them. Of particular interest to gardeners are the last three ranks: family, genus and species. These make up the information most often displayed on plant labels and provide information for growth and care.
How to Classify Flowers
Use family information to explore different kinds of plants that are likely to do well under the same conditions. Some families are fairly tight-knit. Most of the plants in the bromeliaceae family grow best under tropical conditions; kinds sold in northern nurseries may need to spend their entire lives indoors. Other families have a wider variety of relatives. Tomato, potato, peppers, mandrake, morning glory and tobacco all share chemical components that link them in the solanaceae, or nightshade, family. Allergies to one member of the family suggest potential allergies to other members.
Use genus information to learn more about how your plant will grow and look when mature. Latin genus names sometimes resemble common names (genus lilium: lilies; genus cedrus: cedars). Some do not (genus smithatris gives no clue to this new member of the ginger family).
Use species information to learn the history or special distinguishing characteristics of your plant. Cedrus libani, or cedar of Lebanon, takes its species name from its area of origin. A plant name ending in alba will usually have pale or white flowers. Grandiflora describes large flowers. Added to this may often be a common name of the variety, such as bright lights, Joseph's coat or mortgage lifter.
Use plant taxonomy to research plants that do well in your growing area. The U.S. Department of Agriculture's plant database has photographs and growing information, along with information on invasive and endangered plants. The more you know about your plants, the better you can help them grow.