What do white, yellow, green, oolong, black, and pu-erh teas all have in common? They all come from the same plant, Camellia Sinensis (aka tea plant, tea tree or tea shrub). The difference between the teas is mostly in how they are processed.
White teas are the closest to the OG in teas. That is, they are the least processed, with slight withering before being dried and stored. White teas tend to be mild in flavour, low in caffeine and high in antioxidants.
Yellow teas are the rarest. When these tea leaves are left to dry (longer than green teas), they turn yellow in colour and lose some of their vegetative flavours, that are more common in green teas.
Green teas are, well, green. These leaves are steamed or pan-fired to prevent any oxidation and then rolled and dried, producing colours from pale green to bright green with refreshing vegetative flavours.
Oolong teas are made from partly oxidized tea leaves, anywhere from 20% to 90% oxidation. This wide range in oxidation produces a wide range of flavours, from soft floral and peach notes to stronger toasty and nutty flavours. Oolongs are, by nature, highly aromatic and flavourful.
Black teas are made from fully oxidized tea leaves, that is, the tea leaves are left to react with air, heat and humidity before being fully dried. When infused with water, these leaves tend to produce a rich red colour, and rich flavour and aroma to match.
Pu-erh teas are teas that are aged. After the tea leaves are oxidized, they are often compressed and buried in underground caves or rooms. Pu-erh teas produce earthy, full-bodied flavours.
Herbal teas are technically not teas, as they do not come from the plant Camellia Sinensis, but formed from infusions or decoctions of leaves, fruit, roots, flowers, seeds, bark and other plant parts.