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?
Brooklyn Roof Garden 
Posted by matt g on June 19, 2010 at 9:58 pm
I think it depends on the flower…boring impatiens or begonias is probably a bummer, but something with small leaves/flowers that cascades might be an option? (We’ve done okay with lobelia in the past.) I think it also depends if your tree is surrounded by other pots or not, and what’s in those. I say go for it rather than waste the space! (Unless your overall vibe is kind of sparse and restrained…)