We have a sloped planter along one side of our back yard. It's about 8' x 50' long and the slope is about 2 ft from back to front. It currently has gazanias as a ground cover. At the back is a fence that borders our neighbors' yard. About 3 years ago, we put in 3 redbud trees that I was hoping would help screen the view from our neighbor's house. What I didn't know was that our neighbor tends to overwater their yard, and the hill has been pretty wet, resulting in the trees dying this year. Their house is on a slightly higher grade than ours, their yard is level with the top of the small slope in our yard.

Anyone have any suggestions for a small (hopefully flowering) tree that can take a little more moisture than the redbuds? I'm looking for something that would max out at about 15 ft or so. We are in Southern California, a little north of Los Angeles, in one of the more inland valleys (drier overall, hotter in summer, colder in winter). It would be US zone 8B or Sunset zone 18.

Thanks in advance for any suggestions.