Tree

twopenny

I doubt the OP is coming back to the question now.

Perhaps there was something in the first answers that suited.

I do wonder though if a tree is the right answer in a situation like that.

It will shed leaves or petals, cause some green algae to grow in it's shade and it's only a small space

Living stuff doesn't neatly grow to the size and shape you want quickly and with no attention.

GrubbyGirl_2

my first though is who owns the building on the right?  Planting so close could cause all sorts of problems with the roots of a tree and the foundations of the building so you may end up with problems.  Also on a new development think about where drains are going and how deep they are.  Having just having to have drains replaced after my neighbours holly bush collapsed them it cost me £3,000.  Don't be in a rush to plant any tree until you understand what the risks are