I caught a glimpse of one at the Edinburgh Botanical Garden in Scotland several years ago, but it was deep inside a stand of tall trees, and difficult to see. I did see one at Wave Hill Garden in New York once, but it was not in bloom.
Then, on a visit last May to Blithewold Mansion and Gardens in Rhode Island, it was right there, peeking out from behind a big oak. Ha --- I see you.
It is a Davidia involucrata, called a handkerchief tree for the white double bracts that flutter in the breeze. It is also called a dove tree; some think the bracts look like a restless flock of white birds. Still photos don't do it justice --- the beauty of this tree is its fluttering movement.
I was so surprised to finally see one with all its hankies hanging from the branches. A fair number were carelessly discarded all over the ground.
I actually saw a small expensive dove tree for sale at a local nursery several years ago. It is hardy to zone 6, and I used to be in zone 5 but have recently up and moved to 6a on the new map. It can be grown here but needs winter protection.
Blithewold, with its warmer Rhode Island ocean climate, did have this one sited in a protected area. It obviously thrives.
The hankies come out in spring and then the rest of the year it is a medium kind of ordinary looking tree. I may have seen one and not realized it if the bracts were not hanging from the branches.
But, when it is all twinkling aflutter there is no mistaking a handkerchief tree.
I know. I have seen one now.