[ih8samson]

Loving this discussion, I'm very interested in trees and urban landscaping. With all of the talk of elms, blight, and once-trendy nuisance replacements I'm surprised the much maligned (by me anyway) Norway Maple hasn't come up. These things are the absolute worst! The appeal was/is they grow fast and are resistant to everything, in terms of disease and pollution. These traits are also part of what makes them terrible. They take over and outcompete everything in their path. My small upstate NY city gets woodsy on the fringes and Norway Maples have choked out most of the native trees. Saplings are everywhere...growing up through hedges, on the sides of buildings, even in cracks in pavement. When full grown they are not at all attractive - a drab dark green, leaf spot is very common. For a maple, fall color is a huge bust. Quickly yellow, then quickly brown. Leaves hold on and shed slowly. Spring flowers are not attractive or notable, and are very messy. "Helicopters", or seed pods, fall slowly all summer. Summer storms frequently bring down large limbs.

TL;DR - Norway Maples are ugly, messy, invasive and not at all a good tree.