Hi! Looking for a great tree that meets some exceeding specific criteria, and would LOVE your help! I have a very shady courtyard (about 25x25' enclosed by four buildings from 2-4 stories high -- so it only gets very, very brief direct sun, if any) in which I would like to plant a beautiful tree. I'd love it to be somewhat weepy or grow to provide a small canopy, but nothing that will grow too large, as I don't want it to enclose the entire courtyard and block the light coming in to the house. (Or if I can't find something mid-sized and weepy, perhaps tall and slender??) And, my son is highly pollen allergic (to numerous types of pollen). So... anyone have any recommendations for low or no pollen, shade tolerant, small to mid-sized, beautiful, weepy trees? :) At first I thought a Japanese Maple would do the trick perfectly, as I have seen it come up in articles about low allergen gardens, but then when I researched it more specifically, it looks to be more of a moderate-allergen tree. Any thoughts or advice would be so very welcomed. Thanks!