Haha! I know what you mean.. I bought a Davidia Involucrata when it is about 1 year old and that was 3 years ago, and I am still waiting for it to show any buds.. No, no buds again this year..
Same for wisteria .. Another plant bough for £2 and I am still waiting.. I have officially become waity waity! LOL!
The D involucrata might not produce any flowers until it is a teenager.. So longer to wait.. I did fiddle with the pollen and stigma, so I don't really know. I have always loved to use seeds, but lately have a change of heart as the seedlings are often weak and unable to grow to be a proper plant. It would be nice to see a new cultivar ..