Ask Mr. Smarty Plants

You have already stated "why" your  Sophora secundiflora (Texas mountain laurel) died—it is, I believe, the extreme drought we are having.  Even though the mountain laurel is a native and generally considered to be drought tolerant, these are extreme conditions.  You can visit the U. S. Drought Monitor map to see that most of Texas is in "extreme" or "exceptional" drought conditions.  If you 'Google' the terms "trees Texas drought 2011", you will find links to lots of stories about the results of the drought on trees all over the state.  This article, Drought, Wildfire and Forest Health, by Joe Pase of the Texas Forest Service gives information on the effects of drought on trees and how to care for them.  Besides the direct physical effects of the drought on the tree, the stress of drought makes trees more susceptible to disease and pest infestations. To protect your remaining laurels you should water them.  When you water, the soil needs to get a thorough soaking—the equivalent of an inch or more of rain.  (The Texas Forest Service recommends 1-4 inches of water every 10 days.  Use a rain gauge or some sort of container under the sprinkler pattern to measure it.) This will insure the water seeps deep into the soil and will reach the plant's roots there and keep them from growing toward the surface.   Also, the roots generally grow out to at least the same distance as the spread of the tree—the drip line—so watering with a soaker hose at the drip line is an efficient way to get the water to the roots.  Be aware that it takes longer to deliver 1 or 2 inches of water using the soaker rather than a sprinkler.  Mulch spread around the tree can also help to hold in the moisture.  Here is an article, Mulching Trees and Shrubs, from North Carolina State University with good tips on mulching and here is an article from our website, Helping Plants Handle Summer Heat.  It is good that you have not fertilized—never fertilize while your trees under drought stress or any other kind of stress.  The article by Joe Pase (above) tells how to test to see if your tree is really dead and not just dormant and you certainly should try it.  I think, however, that your tree is probably dead.