That western exposure in Phoenix is tough and really limits your choices. Bahia has some good suggestions although here in Las Vegas I've not found the purple hopseed bush(dodonaea) to handle the desert heat well. If you need the height with a width of no more than four feet it seems like you would have to go for a vine. Besides the ones suggested what about bougainvillea? Ours loves the sun and heat and will easily cover your space with quite a bounty of flowers. If you can have something that spreads out a bit more on top the Caesalpinias are very showy and tropical looking. Myrtus Communis Boetica takes a lot of sun and has a more evergreen traditional look with a twist but it is slow growing. The cordias are wonderful (Parvifolia and boissieri) and have fresh looking white flowers all through the summer but they might not want to be kept very narrow. Texas mountain laurel (sophora secundiflora) is another nice evergreen heatloving tree/shrub that blooms in the spring. It doesn't look like a desert plant but does well here although it is not a quick grower. Good idea to wait until fall to start your new project, Maria

I'd agree with the general advice given, but I do disagree about Eastern Redbud(Cercis canadensis) not being drought tolerant. It grows wild well into Central Kansas where many other Eastern species of tree don't make it out to because of heat and drought(average precipitation in this area is as low as 25"(6350mm) and summer highs can be as high as 115F(46.1°C)). It also grows in full sun and nearly full sun in this area. In fact in the beginnings of creeks and erosion channels in the upper 1/3(elevation) of hills in the largely treeless Flint Hills it is one of the tallest trees, forming in some parts somewhat of a canopy growing over the top of Chinquapin Oak(Quercus muhlenbergii) among others. So, it is quite drought and heat tolerant. Although Phoenix, AZ is even hotter and drier than Central Kansas, at least for a much much longer period of time during the year. So, it would most likely do best in full shade and definitely need regular watering, but not excessively like many other Eastern trees would need in your climate. There are other Redbud species which would look very similar and be even more heat and drought tolerant than Eastern Redbud. 'Oklahoma' and 'Texas' are both popular cultivars of Oklahoma Redbud(Cercis reniformis), which was first described from Southern Oklahoma's Arbuckle Mountains. It has a smaller thicker glossy leaf, with generally darker flowers(except the cultivar 'Texas' which has white flowers), and grows a bit smaller than Eastern Redbud. Western Redbud, or California Redbud(C. occidentalis) is native to Arizona, even not too far from Phoenix. It grows all around the Grand Canyon also and I've seen it in full sun surrounded by baking hot exposed rock there(i.e. it was growing out in the open with no other plants around). It has smaller, duller, more blue-green, thicker leaves than Eastern Redbud and grows smaller with multiple trunks. It's leaves are also often notched at the tip giving them a kidney shape to them, but otherwise rounded at the tip and not pointed like Eastern Redbud. It should do well for you in Phoenix. Lastly, Mexican Redbud(C. mexicana) is native from South Central and SW Texas(starting around San Antonio) down through much of Eastern Mexico. It's leaves are even smaller(1"-1.5"(2.5cm-3.8cm) long and wide) than C. reniformis with an undulating leaf edge and very thick and glossy even more so than Oklahoma Redbud. It's also very closely related to and probably should be lumped with Texas Redbud(C. texensis) which has slightly larger leaves, which are less glossy, and doesn't have an undulating leaf edge. Both will grow smaller than Eastern Redbud. Some also try to lump C. reniformis with C. texensis also(putting them all under the name of C. reniformis and calling them all "Texas Redbud"). Historical treatments of these different Redbuds have lumped most all into the same species or just mere varieties, but based on current information I think they are well justified as their own species. But, if a plant tag says something like Cercis canadensis reniformis or Cercis canadensis var. mexicana, etc. you can just delete the canadensis part to get to the scientific names I used. Mexican Redbud, Western Redbud, and Oklahoma Redbud are all in the nursery trade, with Western Redbud being the most difficult to find, at least in my experiences(only found it offered in a couple of nurseries in California). Mexican Redbud is the next most difficult to find, but I've seen it at nurseries in Texas and Arizona. Sorry, but I can't remember which nursery in Arizona, but it was in Tempe or Scottsdale.

don't forget to fertilize with manganese at least twice a year to prevent "frizzle top". many general palm fertilizers do not include this and it can be bought separate (A&P nursery is where i get mine).

toucan I cannot imagine how you'd grow that many tomato plants vertically, though it would be great if it were possible. If you could get containers and somehow suspend them (I'm thinking of 5-gallon buckets for determinates to grow upright in them), you might be able to manage some that way.