I have only been to Disneyland a handful of times (most recently in early December), but there is a definite difference with the foliage there. In most instances, it looks and feels more organic to the park than at WDW. In particular, I am thinking about the right side of the hub as you make your way toward the Matterhorn, the area along the river in front of the Haunted Mansion, and even in Fantasyland right behind the castle. Trees and shrubs just look like they have always been there and belong right where they are.
For that matter, even the new foliage on Buena Vista Street looks great. Of course, possibly my favorite area in either of the California parks is the Grizzly Peak Recreational Area. The landscaping in that area, combined with Grizzly Peak, is fantastic.