Almost every tea enjoyed comes from a specific species of plant known as the camellia sinensis. There are two varieties of this plant that each yield different types of teas, with specific characteristics that define each one. Black tea, called "red tea" in China, is the strongest-tasting variety due to its oxidation time in processing. Oolong tea, known for its flowery notes similar to green tea, is less oxidized. Green tea, the mildest variety, does not undergo oxidation at all and is pan-fried in processing to prevent oxidation from occurring.
Camellia sinensis (or tea plant) is used to make most traditional caffeinated teas, including black tea, white tea, oolong tea, and green tea. This plant originated near the southwest region of China as an evergreen forest shrub. The leaves are glossy green with serrated edges and are similar in both shape and size to a bay leaf.
As the story goes, tea plant was first stumbled upon by accident in 2737 B.C.E. The emperor at the time was boiling water in his garden when a leaf from the overhanging camellia sinensis tree drifted into his pot. The combination yielded a drink that compelled him to research the tree further, uncovering both medicinal and palatable properties.
Two varieties of the tea plant make up some of the most popular types of tea. Camellia sinensis sinensis (Chinese tea) is native to China and thrives in cool temperatures and high elevations. It is commonly grown on mountain slopes, producing a sweeter, gentler taste indicative to both green tea and white tea. Camellia sinensis assamica (Assam tea or Indian tea), on the other hand, thrives in the Assam region of Northern India. This plant is considered more tropical than its Chinese variety, growing larger and producing bigger leaves (due to a climate with plenty of rain and warm temperatures). This variety is used for robust teas like black tea, oolong, and pu-erh.
Although camellia sinensis typically flourishes in tropical climates, some varietals, like the Chinese one, also grow well in cooler, high altitude, climates. In the United States, tea is grown in Hawaii, the subtropical region of the Southeast, and in the cool, mild climate of the Pacific Northwest. Considered hardy to Zone 8, tea plant can be cultivated in backyards in this zone or in a pot in greenhouses in cooler climates.
Many tea gardens and plantations keep camellia sinensis as a shrub, but if you don't prune it, it may grow into a small tree. In fact, some cultivars believe that the taller the tea plant, the larger the root structure, and the more nutrient-rich and flavorful the tea. Tea plant thrives in well-drained, sandy soil and shouldn't be harvested until it reaches three years old.
Harvesting camellia sinensis must be done by hand, as only the top leaves should be plucked. During plucking—the tea industry's term for harvesting—look for young leaves at the top of the plant, particularly those with tips, or small, partially formed leaves. Pluck a group, or "flush," of leaves, taking care to include a small portion of the stem containing two to five leaves and the tip. A flush of just two or three leaves is known as a "golden flush." On rare occasions, the twigs and flowers of the plant are also used. Generally, the plants are kept from blooming to divert their energy to the valuable leaves. However, some backyard growers prefer the pretty white flowers that bloom in the fall.
Tea is harvested during the warmer months when the plant is growing strong. In northern climates, this results in only a four-month window. However, in tropical regions, cultivars may have up to eight months of regular harvests.