Well, you don't have a lot of space, so you probably want to keep the design of the space simple, using two or three copies of one or two kinds of plant. Viburnum 'Blue Muffin' is supposed to stay short (3' to 5'), flowers in the spring and, in the fall, sets blue berries and leaves turn colors. Said to be self-pollinating - mine is too young for me to comment on that. Variegated kerria is doing well in pretty much full sun in my NoVA garden (even though it is said to prefer some shade). It doesn't bloom much for me, but I grow it for the beautiful leaves and the delicate green stems in winter. It spreads, but is not obnoxious. Deutzia gracilis 'Nikko' is a beautiful, fragrant spring bloomer. Stays quite short (2'), spreads horizontally, flexible regarding sun. Could be used in front of one of the other two. Nothing to speak of in fall/winter. Leptodermis oblongais a tiny little thing. The tag on mine says it maxes out at about 15 inches, but mine is a little taller in just its second season in the ground. Healthy, early summer bloomer with fragrant pink flowers over a long period. I don't recall any special fall color on this one. Although you could say they're overused, I really like weigela 'Wine and Roses' and the other dark-leaved weigelas. Healthy, modest in size, their branches form a loose fan shape that appeals to me. Don't know how any of these would do in sand - I've only grown them in clay. Here is a link that might be useful: deutzia

I grow oleanders and they bloom nonstop all summer and remain evergreen through winter. One is in a pot and another in the ground. They can be pruned to shrub form or allowed to get larger. Some people don't like them because they are potentially poisonous, but I've had no problems and we frequently have toddlers and dogs in our garden. If you ever go to Gardens, the nursery near mo-pac and 38th street, they have a gorgeous hedge of oleanders in front. I'm on my second round of Hydrangea, this time I am growing the Oakleaf. The pom-pom hydrangea needed constant watering to make it through summer; and they often lose their leaves in winter in Austin. I love sweet olive, but it lost all of its leaves last summer and looked horrible. I think it was stressed. Barbados Cherry is pretty, as runjbells mentioned. It is evergreen in my garden, and blooms on and off all year. I am in the city near UT, so some things stay evergreen here that don't in outerlaying parts. (My lemon tree has been outside all year and doing great!)

I bought all my manzanitas as 1 gallon pots from Pete at East Bay Wilds. My Dr. Hurd is just about 5 ft after 5 years. It can get to be 15ft if it is happy. I hope it gets to be at least 8 ft. Everything was installed at once in the Fall of 2013. Regarding the desert willow, I have Timeless Beauty in my yard. It is on the smaller side - up to 15 ft. It doesn't reseed and seems to grow on the slower side. I guess it just depends on what your needs are in terms of a tree/shrub. I am making a note of your CA native grass resource. I have a few non-native grasses that I need to replace - thanks! If you ever want someone to come give you some advice on your yard, I can certainly drop by. I am not a design/professional architect, I am just passionate about native plants and will give any feedback for free. I can certainly tell you if you have a Toyon in your yard :)

I agree that it looks like Hydrangea macrophylla. But have no idea why they selected that for a zone 5 garden!! Unless it has winter protection, it is never going to bloom. And considering the difficulty most have with getting the remontant or reblooming (new growth) types to actually produce flowers, even those are not very good choices for a colder zone without protection!! It also looks like it is in full sun. Does it have inground irrigation? ETA: macs can be cut back to the ground and they will regrow quite easily. You will just miss any flowers for a season, even if you were to provide winter protection.