Good to know, and beautiful plant!, although I find the USDA zone system to be only marginally reliable for predicting plant success. More important is the soil, humidity, wind currents, sun exposure and innumerable other variables of that particular spot. When my arid, high-desert zone is the same as humid sea-level Arkansas (for example), comparisons are almost meaningless.
Add the crazy changing climate patterns and it's a total crap shoot. In my opinion 🙂.
I think the success of that plant is likely due more to your gardening skills than anything else.
