Hosta undulata

Hosta sieboldiana grows around one pond and Hosta undulata grows around another. But only the first one spread regularly baby-plants and H.undulata do it never, why? The reason must be that undulata is not a real species but a hybrid made by man. So it can be propagated only by sharing. But anyway, the beautiful leaves has made this hybrid a very popular decorative plant and you may find it in nearly every garden.