I planted 50 paulownia tomentosa trees in Michigan in the 1990s. There used to be folks in the south (I’m thinking GA) promoting Paulownia farming as a great business. That usually means it’s not so great a business.
Anyways, the theory goes they are fast growing trees and in high demand in Asia for cultural reasons. I’ve seen them growing like weeds in Bama, but the larger nicer looking trees I’ve seen were in VA, WV, and the hill country of NC. My conclusion was they grow better in milder summer conditions.
In my experience I wouldn’t call it hardwood. I have some Asian furniture made from the stuff and I’ve layed down engineered flooring with this stuff as the substrate under the veneer. Very soft wood. Kind of like the new Balsa
Sounds like a good material for a bee hive top. How much was it per board foot? I wouldn’t bother to sand off the primer.