Hi, this should actually be cut back in early winter, and divided in spring, when you took a chunk off, did you lift it, or just cut through it while still in the ground?, other than that I can't think of anything you've done that would kill it, Derek.

Oh it’s my fault then. I cut through it while it was still in the ground. I thought it was something I did.

Thank you Derek. I shall now know what to do when I replace it.

Stipa tenuissima is an evergreen grass, so should only need “combing” to take out any dead bits. Mine survive from year to year with this treatment. Only deciduous grasses should be cut back - in late winter, and new growth will appear in Spring (e.g. Japanese blood grass).

Hi Sheilabub, according to the r h s Stipa tenuissima is a deciduous perennial, link below, Derek.
https://www.rhs.org.uk/plants/search-results?query=stipa%20tenuissima

Weird - mine has never died down in years!

Well, whatever the reason, dead is dead so I shall replace it as soon as I can. Its a shame because it looked great where it was That's gardening. I suppose.