The azaleas have just started blooming in the warmer/sunnier spots around the city. I guess they'll kick in over the next few weeks. After that I'm looking forward to the Rhododendrons; I see them all over the city with their big leaves and their closed up flower buds, so I suspect there will be lots of them when they open. I think the arboretum has a nice collection.
While the cherries are nice, I'm particularly attracted to the trees with big white flowers; I'm not sure what they are, maybe dogwood? It's not something I've ever seen in California.