In our area of the country fall color in the garden doesn't just happen, you have to plan it. Most of our native plants are evergreen or they go dormant in the summer and wake up in the fall when the rainy season starts. The predominate color of the native landscape this time of year is pretty much brown. It doesn't mean there aren't any yellows, reds and oranges, just not in the native habitat. However there are many plants and trees that do well in our climate that produce spectacular fall colors and it is up to the gardener to incorporate those plants into their yards if they want to see the change of seasons as well as feel them.
In my SJC gardens there are almost no plants that change colors in the fall and it is easy to forget to add them into the plan at other times of the year so I have been working on putting some in recently. One of them is Boston ivy which I have added to a couple of the bare walls on the house and garage. They may not look like much now, but I am hoping by next year they will add the beautiful shades they are known for in the fall.