Herbal teas are not really teas in that they’re not made from tea plants. Herbal teas are brews of herbs and flowers that are steeped in water the same way that tea is made. The primary difference between a “standard” black tea and an herbal tea (aside from the leaves used) is that black tea is dried and fermented, while the herbs in other teas are usually just dried.
The Chicago Tribune had a great piece recently about how to make your own herbal teas at home. Sun-dried herbs are easy to come by – just take a trip to your garden (or your neighbor’s garden), take a few of the leaves that you like and leave them out in the sun between paper towels to dry. Good choices for making your own herbal teas include peppermint, calendula (pot marigold), bee balm and rose petals – all of which are quite common. It’s best to grow your own so that you know no pesticides will have been sprayed on the plants before you use them