Salvia nemorosa var. plumosa can be quite a difficult plant....it is here, in England. It is quite hardy, as long as it is in well-drained soil. But it is naturally untidy, as the large inflorescences cause the flowering stems to collapse under their own weight. Dead-heading after the 1st flush of flowers should encourage it to flower again. Good luck! At the initial flowering stage, it is stunning.....but seems to rapidly deteriorate, unfortunately.

I tried growing it here in Texas with no luck at all. I do not have much luck with S. nemerosa of any type.

This is not surprising, since this group of sages comes from European alpine areas and are not adapted to hot, humid nights.