I just bought 2 of these from "Wood Thrush natives" online plant nursery.
The plants I received were in good condition.
One is planted on the north side of my garage. The other is planted on the north side of my house. Both places are not directly north, so they do receive some sun during the day. They have both grown to about 4 ft long since I received them 2 months ago.
I'm in Maryland, zone 7b
Update 2024- Something likes to eat this in the spring when it first comes up, so that is very annoying. One of these did not survive being eaten, but the other one did. It has come up every year for the past 3 years, each year surviving being nibbled, each year it gets a little bigger. It is not vigorous or large. Not sure if it ever will be. Maybe it's getting too much shade.

This clematis thrives in zone 6B in Eastern Kansas---far from its native zone. No disease problems or invasiveness if any kind. Love it!!!! I purchased mine from Dancing Oaks Nursery in 2011. I have two plants on the north side of my house and one on the south. The two on the north side get far larger and bloom faster. It is a very well behaved clematis, dying to the ground each year, with no suckering like seen with some of the integrifolias and tanguticas. The flower itself feels like it us made out of a thick rubber foam...totally synthetic feel. It is an awesome clematis, one gracefully growing through one of my redbuds and the other two growing on trellises. It definitely should be more available....especially as rare as it is in nature. New construction encroachments in its native range---parts of the Southeast and Appalachia are the biggest threat to its existence.