Texas designated the crape myrtle as the state shrub in 1997. Crape myrtles are among the toughest, most adaptable, and showiest plants that can be grown on Texas landscapes. The dark green leaves often turn orange or red in fall. Sometimes called "the Lilac of the South", and "perhaps the most beautifully branching flowering tree in the world."

The deciduous Crape Myrtle is among the longest-blooming shrubs (up to 120 days), and varies in size from dwarf to large shrubs or small trees. It has dense clusters of crinkled, crepe-papery flowers in white or shades of pink, red, or purple, and lives happiest in hot-summer climates.

Source:

Stop the Crape Murder by Greg Grant: Dept. of Agriculture

Links:

Crape Myrtle Lagerstroemia: Wikipedia
Crape Myrtle: Texas Agricultural Experiment Station
Period Gardener - Pre 1850 substitutes: Westville Mirror
USDA: Hot Links for Teachers...Cool Sites for Kids
Garden Source: Flower and Garden articles
State Flowers & Plants - 50 States List - National Flower