Epimedium grandiflorum 'Rose Queen'
'Rose Queen' is said to be the western name for 'Yubae', which is a very old Japanese cultivar. As far as I can see, this one has paler tips to the spurs on the petals,
but my 'Yubae' is a very recent arrival, and it may need time to settle.
25th May 2013
References:
Barker, David G. - Epimedium and other herbaceous Berberidaceae, Hardy Plant Society, 1997
Stearn, William T. - Epimedium, 2002.