Decaffeinated teas are mostly green and black teas that have been decaffeinated through a special process. However they may still contain up to 3% of the original caffeine content.
Herbal "teas" or Tisanes are any herbal infusions not made from Camellia Sinensis (tea plant). Tisanes may be made of flowers, leaves, fruits, seeds, roots etc. They are naturally 100% caffeine free. The examples of herbal teas are:
Rooibos (red tea)