There’s a good reason for this: Hue uses ZigBee, not Z Wave, so there is no way for these things to work directly together. However, there’s good news! This post details how to setup a Java application that will allow you to bridge commands from the Echo to SmartThings, so you can use your existing ST configuration and Z Wave switches from Echo.
I’m running this at home right now and it works great. Echo picks up the commands and issues the response to ST quickly and reliably.