Texas Gardening: What is this purple bush / vine?, 1 by WombatFamily

WombatFamily wrote:
We have just moved to Brenham (about midway between Austin and Houston) and my daughter and I spied this flower on a bushy / cascading viney thing in downtown. The plant is either a creeper or a vine -- I think where we saw it it was probably potted with a climing pole, but it's hard to tell because it was basically a 5' cascading triangle spilling out onto the sidewalk. Here is a picture of it.... anyone know what it is? We'd LOVE to plant one on our property.