Hi Bonehead!
I think it was 5 years ago I got a P. lutea seedling at Kruckeberg Botanic Garden in Shoreline (Seattle). I do not know what variety. I planted it in dry shade under a cedar tree, because they had some in their woods that somehow did well and bloomed anyway. They were tall and very straggly, but looked healthy (maybe 8-10 feet tall). Mine is now almost 6 feet tall and wide, and growing fast, but leaning out towards the light. It never wilts no matter how I neglect it. This is the first year it bloomed, and here are photos. Last year I saw a giant hedge of them at the Washington Park Arboretum in Seattle- it looked to be about 10' tall and 10' wide!!!!