White tea is made from the same plant as Black, Green and Oolong teas, but the leaves treated slightly differently. Unlike other varieties of tea, the youngest growth on the tea bush is picked for White teas – before the leaves have opened. They are then dried immediately to stop them oxidising.
The amount of oxidation is what separates the different types of tea; White tea is oxidised the least, then Green, Oolong, and finally Black tea is allowed to fully oxidise (which gives the leaves their characteristic black colour).