Hello from Palo Alto! The Berberis species need irrigation over the summer but have amazing fall color ('Rose Glow' and 'Orange Rocket' are a couple of my favorites); same for the native Cornus sericea and Cornus stolonifera. Lagerstroemia is more summer-dry and known as a tree but there are quite a few "shrubby" cultivars available these days if you have a smaller space. The native Rhus trilobata needs a lot of room but has good color and doesn't need summer water. For a pergola, arbor or large trellis, the native grapevine Vitis californica 'Rogers Red' is incredible and also drought-tolerant. Acer circinatum is a vining shrub with gorgeous color that appreciates summer water and can tolerate some shade. Finally, blueberries (Vaccinium spp. and cvs.) make a fantastic landscape plant, although they also need regular water, and their fall color is incredible. I look forward to seeing what other folks suggest!

My spirits lifted when I saw this post, but just as quickly fell when I noted you're in z9b. To say I'm outside your zone would be an understatement. On the other hand, Verdance has recommended several shrubs native to the upper Midwest. An example is Cornus sericea, which likes its feet moist to to the edge of wetness. Another is Vaccinium. This genus covers a lot of ground, with some being bog plants. To grow these in their natural way would be amazing, and I must learn more about Palo Alto.

Fothergilla is a plant that puts on a splendid fall show in my garden.

My current favourite (changes by the week) is the gorgeous dwarf mountain ash - sorbus reducta. Tbf, I love all the sorbus, unreservedly, but for small spaces, this slow-grower is a delight. I haven't got started on the malus yet though...

Oak leaf hydrangeas have pretty winter color!