If you are looking for some great information on Perennial Plants for your South Texas Landscape, below is an excerpt from Texas A&M AgriLife Extension Service.
For more great info and a listing of some Local Perennial Favorites, see the fill post here: http://bexar-tx.tamu.edu/earth-kind-horticulture/best-plants-for-bexar-county-south-texas/perennial-plants-for-south-texas-landscapes/
Perennial plants may be defined as those which endure or persist from the same root part year to year. Once a prominent part of nearly every Texas landscape, perennials are often overlooked by today’s gardeners and nurserymen. Although many species still can be found in private gardens, their availability is often restricted to sharing among friends and neighbors.
Most perennials are easily propagated by division, seed or cuttings. Division is particularly successful since it not only provides new plants but is often necessary for the continued vigor of plants. Perennials can be highly useful and attractive in the home landscape. They often persist for many years and usually require less maintenance than annuals. They can provide long seasons of color and cut flowers while enhancing overall landscape development. If a perennial border is more than you care to attempt as your initial experience with perennials try adding a few to existing plantings. Many perennials have attractive foliage and are an asset even when not in flower. Division is an important cultural requirement of many perennials. Without an occasional thinning, most of these plants will slowly lose their vigor. Most perennials will tolerate relatively poor growing conditions but respond very favorably to well-prepared planting areas containing high percentages of organic materials and moderately high fertility rates.