I have another Clero that does the same thing - it doesn't seed itself, it 'runs' underground and pops up 10ft. away from the parent plants. The flowers look much like your Cashmere Bouquet but have longer shafts and the leaves have purple on the backs so it's a very attractive shrub. But becoming a real pest!
Clero quadriloculare - the Shooting Star Clerodendron. It blooms beautifully in the winter IF it doesn't get cold! But if the cold gets to it before the flowers open, it drops all its leaves and looks terrible for 3 months or more.
Second pic, the runner made it all the way under the wall, and happily showed itself in front of our address. Of course they like the middle of the gravel pathways as well - guess there's more light out there.
