I read somewhere that ringing a majestic tree with a base of flowering annuals is like forcing your dog wear frilly underwear or a tutu. Something like that. Now ever time I a ring of impatiens or begonias around the base of a tree, I laugh.
But, we do have flowers planted along with the few small trees that we have in our roof garden. We just have so many plants we want to grow and just a few containers. What do you think about flowers under potted trees?