The tea plant is an evergreen of the Camellia family that is native to China, Tibet and northern India. There are two main varieties of the tea plant. The small leaf variety, known as Camellia sinensis, thrives in the cool, high mountain regions of central China and Japan. The large leaf variety, known as Camellia assamica, grows best in the moist, tropical climates found in Northeast India and the Szechuan and Yunnan provinces of China. The plant produces dark green, shiny leaves and small, white blossoms.
According to an old Chinese saying, "superior tea comes from high mountains". The altitude and mountain mists help shield against too much sunlight and provide the proper temperature and humidity to allow the leaves to develop slowly and remain tender. As with wine, the quality and taste of a particular tea is influenced by both the environment (soil, climate, and altitude) and the tea maker (who decides when and how the leaf is plucked and how it is processed).
Most tea plants have a growth phase and a dormant period, usually during the winter. The leaves are plucked as the new tea shoots (or "flush") emerge. In hotter climates, the plants have several flushes and can be picked year-round. In cooler conditions at higher elevations, there is a distinct harvesting season. Leaves from the earlier flushes, usually in the spring, give the finest quality teas.
There are five main types of tea: green tea, black tea, oolong tea, white tea. and pu-erh tea. All tea comes from the same plant. The specific variety of tea plant and the way the leaves are processed after harvesting determine the type of tea that is created.
It is possible to make any or all of the five types from leaves of the same plant; however, most producing areas and countries specialize in only one type. Japan produces almost exclusively green tea, India mostly black tea, Taiwan specializes in oolong tea and all types are produced in China.