The common or Japanese camellia (Camellia japonica) is an upright to spreading evergreen shrub or small tree, growing 10 to 20 feet tall and 3 to 10 feet wide at maturity. The dark green leaves and red flowers describe the wild form of the species, but for centuries gardeners bred and selected different mutations to increase the range of flower sizes, forms and colors. Typically, common camellias bloom in winter and early spring, but newer cultivars tend to have longer blooming seasons, extending even into mid- or late spring.
Place in the Plant Kingdom
Camellia japonica is a flowering plant and therefore considered an angiosperm. Among the flowering plants, it is further classified as a dicotyledon (often called simply a "dicot") because its seeds sprout with two embryo leaves and the vein arrangement in its foliage is in a branching pattern (not parallel).
All species of camellias are lumped into the tea family, Theaceae. Other genera (plural of "genus") in this family besides Camellia include Franklinia, Gordonia and Stewartia, all of which are woody trees with camellia blossom-like flowers. Camellia japonica is but one species in the genus Camellia, as in total there are about 250 species that are all native to Asia.
Species Camellia Japonica
The Flora of China's online database mentions that there are two naturally occurring varieties of Camellia japonica: variety japonica and rusticana. Some taxonomists don't recognize these natural varieties and simply consider each a distinctive, separate species. The International Camellia Society (ICS) classifies the common camellia with three subcategories: subspecies japonica, subspecies japonica var. macrocarpa, and subspecies rusticana. Moreover, the ICS notes that one type of camellia from Japan that is commonly called "Higo camellia" is likely a mutation of one of the forms of Camellia japonica.
Cultivated Varieties (Cultivars)
Today, common camellia plants produce any of a wide array of mature growing heights, habits, season of blooming and flower size, color, and form. These cultivated varieties are assigned a name by the plant breeder and typically are registered with a governing body so there is a universal understanding of what characteristics create the cultivar and that no two cultivars are confusingly given the same name. The ICS recognizes that many modern cultivars of Camellia japonica may no longer possess pure genetic lineage as many species of camellias can be cross-pollinated to produce many different seedlings with wildly variable physical features.
Common camellia plants are widely grown and selected by horticulturists for their floral beauty. Thus, the plants are often grouped by more practical, descriptive names to differentiate among the hundreds of cultivars extant today. For example, shrubs are grouped based on the form of the flowers they produce. There are six categories: single, semi-double, anemone-form, peony-form, rose-form double and formal double. In the United States (and often across the Northern Hemisphere), camellias are also grouped as to season of bloom. Blooming periods include "early season" (before January 1), "midseason" (January 1 to March 1) and "late season" (after March 1) according to "A-Z Encyclopedia of Garden Plants." The flowers can also be grouped according to their flower color (the Berlese Color Chart) to differentiate among all the tones of white, pink and red.