I've gotten quite a shock when I entered the greenhouse. Apparently, this mystery 'plant' was actually a tree. I've completely guessed wrong by studying the leaves, so this little guy threw me off big time. I haven't had much experience with growing trees from a sapling, but it seems like I did VERY well to receive such a growth.
As more plants bloomed and some new stock came in, I hoped to see this mystery tree get larger. But time will only tell.