Hosta Knockout is a medium Hosta of about 12"-16" in height & with a spread of about 20" at maturity. The growth is medium to slow. Leaves are broadly ovate with thick substance. Since it has such a wide variegated margin of white which tends to be thin in substance, this cultivar often suffers from rips along the leaf edge. Grey-green leaves with a yellow changing to a creamy margin, margin gets brown in hot summers. It bears near white flowers set on scapes of 24" tall from late June into July. Holds up well against slugs and is sun tolerant as well.