In message , Kay Lancaster
writes
That's pretty much got the look of a grass. Round, probably hollow stems?

But it probably turns out not to be a grass. Carex pendula, a fairly
common garden inscape, or at least something close to it (the flowering
shoots are usually more spreading).

Can't really id it beyond this without a good closeup of the inflorescence
and flowers, and maybe not even then from photos.

Kay

--
Stewart Robert Hinsley