Perhaps containerizing it will control the spread?

Hi Carol! I think that might be the only solution. It's sending out underground runners (like bamboo) but I am wondering if it is also spreading \seeds. The vigor of this plant scares me...lol. It's right next to be a/c unit and its corral which sits on a concrete slab and the plant runners have made it to the other side of the corral.

I've never seen a clerodendrum that doesn't do that. Containerizing is only a partial solution. I've seen them send runners out through the drainage holes in the pot to spread into the ground.

That's one thing saucers are good for...

I think this one is too big to containerize it. The trunk is about 3" diameter. Somhow the shrub managed to turn into a little tree. I pruned it hard yesterday but that's not going to help what's going on underground. I would try root slicing it but without putting up barriers I fear it would just encourage it to send out more roots.