Murph, I'm sure you saw the wisteria vines. They have purple/blue flowers that look like bunches of grapes (see attachment). They are in full bloom right now. They grow on long vines like grapes and are common throughout the south. Also, the redbud trees have purplish blooms, but if you look at Wrought Iron Harv's post earlier in this thread, you will see one of those.
Keller? College? I thought the only thing in Keller was lots of "old style" buildings with Austin stone and brick. I'm curious about which college your son is in? TCU? NTSU?