Epimedium grandiflorum 'White Queen'
A very large flowered form. Not to be confused with 'Silver Queen' - they are quite different.
28th April 2006
2nd April 2009
18th April 2010
18th April 2015
References:
Barker, David G. - Epimedium and other herbaceous Berberidaceae, Hardy Plant Society, 1997
Stearn, William T. - Epimedium, 2002.