I live in a neighborhood, and my house faces north, the garden is on the south side. I've got neighbors with *tall* trees on the east, west (where there is also a hill), and south of me, nothing I can do about those. We've taken down two trees in our yard on our SW corner, that gave us about another 90 minutes of direct light.
I've got a friend growing in the city where the lot sizes are even smaller, and he gets a couple of hours of dappled sunlight per day, and he manages to grow weed. His plants aren't as heavy as mine, but it smokes well.