I'm not sure what it is, but the trees and grass seem too vibrant for the evening setting. Perhaps they need some more blue all around or at least on the tops and bottoms that aren't close to the lamps. The dark tree just to the right of the stone urn/pillar has a good color and seems about right. The ones closer to the viewer are just a little too sunny. This could just be my personal opinion. I think it looks lovely right now and sometimes it's best not to question a good thing!The trees in the distanced and the water reflections are extremely successful. I love the soft light from the lamps, too!
I really appreciate the feedback! And it makes a lot of sense. Now that you say it it really stands out to me. I think i just have too much fun painting trees and grass :-)