Windows. Not meaning to sound like a smarta$$, but if you don't have near neighbors on that side and it is not all closets or something on the inside, I would add windows. Looks like you have a houseplan for a zero lot setback style subdivision, but are on a bigger lot. Other than that, trellis with a vine. Or esplanade trees (and I know I spelled that wrong), where the trees are trained flat to the wall. Don't have plant suggestions, not familiar with what grows well in your part of the country.

Ok, I try again. Love the mockernut. Don 't love the wax myrtle, much too unruly for a small yard, requires much pruning if left in a bed. Much prefer crape myrtle of the two. I bought: ginkgo biloba because of yellow leaves and good root system. Swamp cypress just because I love them, and they stand up well to winds. One betula negra, river birch with 3 trunks, as close as we'll ever get to the lovely white birch up north, 5 Italian cypress as punctuation marks for the north property line where nothing is planted but where a polite two-faced landscaped bed is in the process of being dug as we speak. Then somewhere there will be one or two white Natchez crape myrtles, acer palmatum Japanese maple with lacy leaves, and a couple of confederate roses to the south property line. They will grow quickly and screen the sunporch from view by passing traffic. Meanwhile this summer, I am creating some shade for my plants with a few big umbrellas and a 10x10' gazebo tent which JCPenney's had half price last week. The gazebo is being set up inside my ROOFLESS cement block garage which I fancy looks like an old ruin--which it is actually--but which has potential for containing my potted plants around its cement floor and hanging from its cement block walls. With the oak and sweet gum trees gone, it doesn't fill up with acorns, leaves, and spikey balls. One day, this will become my greenhouse. I plan to attend the Botan Garden plant sale as early Friday as I can get there. Did not know they started on Thursday. And thanks for the tip about Bellingrath selling trees. It is time for us to visit the gardens again anyway.

Well that's quite a large wall to work with and anything that helps to shade/screen it will, no doubt, cut down on the electric bills. Besides trees/shrubs, you might consider a tall trellis/vine as well. You could also train a non-vine type plant on it such as the evergreen (orange/red berried) Pyracantha. The birds will thank you. Trees that have similar orange/red berries are Yaupons and Possumhaws. The Yaupons are evergreen the Possumhaws drop the leaves and show just the berries. Then there's the sun loving, orange flowered miniature pomegranite that gets about 10-12 feet. But if you don't want the fruit then don't do it. Keeping with the natives, there's always the fragrant Mountain Laurels. Very slow growing so buy one that is fairly mature. Another lovely native is the Vitex with its lavender blooms that are enjoyed by bees and hummingbirds. It's deciduous. As far as small trees go, my new favorite is the Tea or Sweet Olive (Osmanthus Fragrans). Fragrant, evergreen, and can be used either as a shrub or a specimen tree (find one with a single trunk). As for evergreen junipers, there are varieties of Sky Rocket Junipers (or rocket junipers) that might be appropriate. They keep a fairly slim width and height under 20'. Attractive, sun loving and drought tolerant, but I'm not sure how they do in Texas. There are many more 'smallish' trees that could be used in that space. Too many to name.

I just planted 6 within the past two weeks, the blooms are beautiful and they seem to love the heat! At the nursery, the lady who helped me told me to expect them to get around 15-20' tall at maturity. Best of luck!