On 27/05/2019 10:02, Jeff Layman wrote:
Seen yesterday at an NGS garden. The leaves are about 10 mm long.The
whole plant was about 80 cm high and 150 cm across. Apparently fully hardy.

Maybe a Spiraea?

https://ibb.co/NN2GXkx


I had to hit my files to remind myself of the name, but I think that
this is Stephanandra incisa, and probably cv. 'Crispa'. Wikipedia tells
me that Stephanandra has been sunk in Neillia, and it is now Neillia incisa.

--
SRH