I don’t know of any tea grown in the USA (but I’d love to hear about it). Here in Minnesota it’s cold, and the plants would simply freeze. Light-style teas often grow in colder, high-mountain farms to give it a sweet flavor, but there are many famous tea sources around the world.
The tea plants grow like a short shrub, but they are actually like trees. A new plant needs to grow 3-5 years before reaching harvesting size. They are trimmed and maintained to a reasonable waist-height with a flat top. The flat top allows new leaves to grow out the top for accessible trimming, and a large area for new leaves to grow towards the sun.
In Taiwan, the tea leaves are often hand-picked. Harvesting and processing is a delicate, fast-paced process. The processing starts immediately and continues day and night until it’s ready for sale. Choosing the date of harvest can be a difficult decision. A few extra days growing time could give a good increase in harvest size, or result in an undesirable change to the flavor. The size of the leaves affects the fragrance and flavor of the tea.
Harvested tea is immediately brought to the processing site near the farm, where drying starts immediately. The processing includes many steps: various styles of drying, rolling, compressing, fermenting and roasting. This process defines the type of tea (green, oolong, black, and many others) A light, oolong tea will take a couple days to process, and the tea masters operate around the clock until it’s done.