I had the same issue and went with Crepe Myrtle. You may need to get some dwarf variety to keep them at 6-8 feet.

Jatropha

You could try firebush. It grows very fast, and dies back in the winter when you'll need that sun to warm the house. Then it comes back up and grows very quickly in the spring. Just remember that most fast-growing trees are not very hurricane-friendly.

For summer only plants (from rhizomes), I suggest Gloriosa Lilies. My west wall hottest spot (and shallow depth dirt) has been very kind to the Gloriosa Lily bulbs I planted a few years ago. I had remembered they grew in a tangle in the grey sand by our hottest wall at our family home, rarely given water. I do water mine, though. Each summer, more stems than the previous year pop up and the "older" stems that reappear with new branches have multiple red and yellow blooms. 6-foot tall main stems. I stake some, but tie most to the creeping fig that covers the (hot) wall behind them. (Unfortunately, that fig needs watering due to the heat.)