Depends on what kind of tea you want to grow. I live in Dallas (Zone 8a) and I'm starting to grow a bunch of different plants and herbs. One in particular is Jiaogulan which is a Japanese tea vine. Many people swear by its healing properties. And it's hardy to my area. Echinacea and Chamomile both grow very well in Texas heat. Some others I have started from seeds are spearmint, marshmallow, catnip, tarragon, fennel, navajo tea, and holy basil.