Both Grewia asiatica (phalsa) and Grewia occidentalis (crossberry) grow well in San Diego. There are Grewia occidentalis trees/bushes in Balboa Park and in Sorrento Valley, blooming just fine but not setting fruit. Evergreen nursery on Carmel Valley Road had rather large Grewia occidentalis, trained as trees, with fruit, in stock this winter. Your best bet would probably to talk to the Evergreen staff, to figure out what Grewia needs to set fruit: whether it's just a matter of the plant size or not. I have several Grewia species, including the above two, growing from seeds. Some are blooming but none set fruit yet. They are easy plants to grow (or hard plants to kill - depends on your perspective), and pretty, but don't expect fruit anytime soon. Both Trade Winds Fruit and TopTropicals have Grewia seeds occasionally, that's where I've got them.
Kindest wishes,
Dimitry
