Bergamot? What is that? Obviously, having never heard of this before, I do not have high hopes that it is native to the Northeastern United States. Let's see what we can find...
Well, it seems that it is a "sweet lemon" that grows near Bergamo in Northern Italy. Although the fruit is inedible, the essential oil is used to give Earl Gray tea its distinctive flavor. If you are to use this in your tea blend, you will probably need to find a supplier of essential oil.
Is there a suitable substitute for this? I see references to "sweet lemon" or "sour orange", so would it be possible to use a combination of regular oranges and lemons? That would be some thing to experiment with.
Interestingly, Bergamot is phototoxic so you should avoid massaging it into your skin if you are going out into strong sunlight. It has a long history of being used in potpourri and perfume recipes.