At this moment, camellia sinensis is not offered in cold hardy varieties. It is a warm region camellia. It does well in Zone 8 and can venture its toes into some Zone 7 areas where it may suffer winter damage at times but will recover. Your best bet is to grow it in a greenhouse type of setting during the cold winter months. There are cold hardy camellias that get around this problem by blooming early (called the Winter Series because they bloom in early) or late (called the April Series because they bloom in mid-to-late Spring). This allows the plant to survive the coldest temperatures while the much tender blooms survive warmer early-late winter temperatures. Unfortunately, "the" tea camellia sinensis is not one of them yet. One can still hope.

Oh wow. Thanks. For some reason I thought there was a few varieties.

I have a few C. sinensis of varying hardiness. The hardier tyopes can take at least mid single digits. A small-leaved form sold by Camellia Forest is rated to zone 6, but I've not had a zone 6 winter since 93-94. You can get good regrowth from a Camellia by banking mulch around a plant from mid December to March.