I just wanted to provide a short update. I have decided to wean myself from green tea, and it's as much because I don't want to be dependent on something I can not grow in Maine, as it is the caffiene content and its effects on my body.
I'm still drinking green tea, and I will continue, because I have, something like, seven boxes of green tea in my cabinet (stocking up, you know?), and I won't waste it. So, I've been having a few cups in the morning, and in the afternoon, I'm switching to Roiboos tea, but red tea is grown, almost exclusively, in Africa, and so it won't be a long-term substitute.
I did, however, develop my own interesting blend this evening. I used chamomile, sage, one clove, a dash of cinnamon and a dash of cardamom. I realize that none of those spices grow in Maine, either, and I will continue looking for some spicy, earthy herbs to make my tea (maybe some tarragon ...??), but my feeling is that I could substitute green tea with my personal tea blend for a fraction of the cost of the green tea (assuming I grow my own chamomile and sage), even if I buy the spices, and I'm not positive, but pretty sure that the spices aren't as addictive as caffiene. So, if I can no longer access them, at least I will have already gone through the withdrawals ;).
One other benefit to my tea blend is that I drink it with honey rather than sugar, but I prefer green tea with sugar. When we start harvesting honey and start eliminating sugar, I'll want to have made the transition away from sugar, too. Sugar is also addictive, and something I will want to eventually wean myself off ;).
Thank you everyone who offered suggestions and encouragement.
And if anyone knows of a great, spicy herb that likes cold weather, let me know ;).