A quick look at Denver weather says you all are getting nights into the low to mid 30's. The plant came from an area that is ten degrees warmer than that. The plant is likely reacting to that change. Cold slows the down.
I'd also check that soil or gravel you have it in--if you surrounded the existing root mass with the same, roots might be suffering from being dry on the outer portion of the root mass and wet interior. Far different soil types in the same container can kill plants or slow them down. Root are very reluctant to cross over into different soil types.