I found another article that said that besides coffee plants, various citrus plants have caffeine in their nectar. So I guess, if you have citrus flowers, bees will stop by and get their caffeine...makes me wish I had some citrus! If I could find a citrus tree I could put in the ground that would provide good enough citrus fruit and still tolerate the cold out here, I'd do it. Lately, I heard about one, "Orange Frost", which is very cold hardy, but it's not widely available yet.