‘koji’ has been listed as a variety of E. sempervirens by some authorities. Certainly with us it is far more evergreen than most E. grandiflorum cultivars we have, so this may be correct. Having said that one or two of our E. sempervirens are fairly deciduous! This is a fairly strong grower which has survived while other weaker E. grandiflorum varieties have faded away around it, due to tree root competition, we suspect.
General information on Epimedium grandiflorum
Distribution – Japan (Kyushu, Shikoku, Honshu and Hokiado). Northern Korea and southern Manchuria.
Description – A medium sized fairly deciduous species with widespread distribution through Japan etc. growing in deciduous woodland. It was introduced to Great Britain in the 1830s. With its wide geographical range through the various Japanese islands etc., a good deal of variation has occurred. Flower colour of the plants found in the wild varies widely: yellow, white, pink, lilac and reddish to purple. Add to this the large number of plants attributed to E grandiflorum that have arisen in cultivation and there may be hundreds of cultivars already named.
Epimedium grandiflorum 'Koji'