https://lostpinesyaupontea.com/pages/yaupon-tea-caffeine-con...
I have several yaupons in my yard's landscape and have dried the leaves as described and made tea. It has a good flavor and is pleasant to drink. I drink so much coffee though that I could not tell whether I was getting any caffeine. I just felt normal.
The bushes grow to small trees that can, over time, completely cover a landscape since the send up sprouts from their shallow roots. This is a sustainable, easy to grow, source of caffeine for areas where it will grow.
The berries are excellent food for birds in winter. Our trees were attacked and stripped by flocks of birds in the last days before the big freeze this February. I thought the trees had frozen out but they are now as bushy and vibrant as ever.
As far as real coffees from their native environments are concerned I would gladly volunteer my place as a test site for growing a drought tolerant, freeze-tolerant variety as long as I get to taste test it.
I drink my coffee New Orleans style with chicory. It is the most delicious morning, noon, evening, and night drink that I have ever had. Smooth, non-acidic, rich, vibrant, fragrant, just plain great liquid energy.