C. erecta is a native in TX, so can't be invasive, by definition. Looking at USDA plants database, there are many Commelinas known to be present in TX, both native and introduced. The blue doesn't look dark enough to be C. communis, but that's not much to go on for a pic on the computer, where color is sometimes a bit off. C. erecta is what I thought when I saw the pic. I love dayflowers too! The lack of a 3rd petal eliminates most other species from consideration, but does include C. communis.
http://plants.usda.gov/checkli...
(Enter Commelina in the box at top, click the box for TX, click search, to see the species known to be present in TX.)
