Hosta hypoleuca Urajiro medium

This is a hosta we acquired many years ago under this name. We don't have much information about it, but it has been a slow grower for us. According to hostalibrary.org, hypoleuca in Japan is called Urajiro Giboshi, the "white-backed hosta". Whatever we have, it has pointed, gray-green leaves with whitish undersides. We estimate that it grows 15" tall and 36" wide. Lavender flowers in summer.