To answer the question of ” What is tea?” we should explain first that all teas comes from one plant, the Camellia Sinensis.
Camellia sinensis is a species of evergreen shrub or small tree. The leaves and leaf buds are used to produce tea. The reason that there are so many different categories, flavors and blends are mostly in the processing of the leaves.
So, white tea, green tea, oolong, pu-erh tea and black tea are all harvested from the same plant. But the leaves are processed differently to attain varying levels of oxidation. The packaging is also different, a teabag is filled with smaller dust then the loose tea leaves.
Rooibos and herbal tisanes are not made from this tree plant. They are officially not tea, but tisanes or tea like beverages. That explains also the difference in caffeine, since herbal and rooibos don’t contain any caffeine.
Origin of Tea
The origin of tea is not clear. Camellia sinensis var. sinensis is probably native to the western Yunnan province of China, while C. sinensis var. assamica is native to the warmer parts of Assam (India), Burma, Thailand, Laos, Cambodia, Vietnam and southern China.
Camellia Sinensis is an evergreen shrub, which can grow up to 17 m high. In cultivation, it is usually kept below 2 m high by pruning. Camellia sinensis is mainly cultivated in tropical and subtropical climates, in areas with at least 127 cm. (50 inches) of rainfall a year. Tea plants prefer a rich and moist growing location in full to part sun. Commercially the shrub is cultivated from the equator to as far north as Cornwall and Scotland on the UK mainland. Many high quality teas are grown at high elevations, up to 1,500 meters (4,900 feet), as the plants grow more slowly and acquire more flavor.
Tea plants will grow into a tree if left undisturbed, but cultivated plants are pruned to waist height for ease of plucking.
Varieties of the plant
There are two main strains of this shrub. These are Camellia sinensis var. sinensis (Chinese tea) and Camellia sinensis var. assamica (Assam tea, Indian tea).
Camellia sinensis var. sinensis is hardier than Assam tea, and has relatively small and narrow leaves. Its leaves are used to produce green tea and China black tea.
Camellia sinensis var. assamica is much taller in its natural state (than when cultivated) and can grow into a loosely branched tree to a height of about 17 m. It is a less hardy variety with larger, rather droopy, leathery leaves, which are used to make Assam (Indian) black tea.