Ask Mr. Smarty Plants

When we start trying to figure out what is wrong with a plant, we first try to figure out what plant we are talking about, and whether it is native to the area where it is being grown. When we searched our Native Plant Database for member of the genus Gaura, we found 14 species. Of those, 8 are native to Texas, and Gaura brachycarpa (Plains beeblossom) is native to Collin County, according to this USDA Plant Profile map. That doesn't mean that is exactly what you have, and this plant is very widely hybridized, which means we really don't know exactly what its characteristics are, but this will help us get close. By following the plant link above to our webpage on this plant, we found:

"The genus Gaura is composed of rather weedy plants, with leaves borne singly on  spikes or racemes, or are branching. The genus is easily recognized, but the species are sometimes difficult, due partly to a great deal of hybridization."

We also know that plant is generally short-lived. Your plant may have nothing at all wrong with it, it may just have achieved its "Die By" date.  They can be propagated vegetatively by rhizome cuttings in spring or by division of mature plants; tip cuttings in vermiculite and under intermittent mist root in 2-3 weeks. Possibly your plants are already too far gone for this to work, but the next time you plant gaura you might consider dividing the mature clumps every couple of years.