This is a non-registered seedling of H. montana from Japan. It forms a large size hosta with green leaves and a semi-upright form. The key trait is that it bears double, white flowers in July.

An article about the cultivar H. 'Yae-no-oba' by Warren I. Pollock in The Hosta Journal (2001 Vol. 32 No. 2)  states that, "This cultivar is a selection of H. plantaginea 'Aphrodite' growing in Ralph "Herb" Benedict's garden...according to Ron Williams of House of Hosta in Green Bay, Wisconsin, who introduced it, is a "vast improvement over H. plantaginea 'Aphrodite' as it blooms profusely each year"...(Pollock continues) I've also found that these H. plantaginea plants flower better if the weather is hot: in the upper 80s and higher along with high night temperatures...."Yae" means "to have two of something" in Japanese, in other words "double"..."