Cotinus are prone to verticillium wilt and I have seen that pathogen take out a number of them.......somewhat similar to the way you described. The plants were typically subjected to some sort of stress that allowed infection....like drought, although it usually doesn't happen quite that rapidly.

I would suggest you wait to see what happens. Often with VW, the leaves will persist on the branches indefinitely, even though dried up and dead, so that could be an indication.

Thanks. I looked up photos and that's exactly what it looks like.

A cross section cut of a stem shows a dark circle just inside the outer layer of bark. I assume that is the fungus. I'll have to strip a branch to see if it looks like the photo in the link above. It looks like the entire plant is dying now. I guess it's time to yank it.

You will need to be careful with what you replant in that area. Once the VW pathogen as been activated out its dormancy, anything susceptible is likely to become infected almost immediately.

Is there some way to check a plant's susceptibility before buying something?

Yes. There are various listings out there. Here's one: Verticillium wilt resistant plants (scroll down).

There are not many VW resistant shrubs that will offer coloring similar to the smokebush, if that is a factor. Although difficult to find listed, ninebark, Physocarpus opuifolius, is and does come in deep maroon/burgundy leaf colors.

It could have dried out if the rootball was small and rootbound and never spread much into the surrounding soil that you say is sandy. On top of that there's that persistent breeze on that flat plain between Sequim and Port Angeles next to the Strait. You must be near Agnew.

You'll know when you pull it up if it dies. Either it has a lot of roots or it doesn't.

Kind of between Agnew and Carlsborg but near the coast. We're not far from the Dungeness Spit. There is wind. It was growing very well for two years and I don't think it was rootbound, but we'll see what the roots look like soon enough. We have Hoypus soil, drains very quickly.

Following up on this thread, the plant was indeed well rooted. I'm pretty sure the culprit was verticilium wilt.