A miniature to small size (5 inches high by 9 inches wide) hosta, this cultivar is a hybrid of two Tardiana-type seedlings which was registered in 2005 by Peter and Jean Ruh of Ohio on behalf of the originator, Heinz Klose of Staudengärtnerei Klose in Germany. The foliage starts the season deep blue-green but changes to dark green as the summer progresses. Its leaves are lanceolate, moderately twisted, slightly cupped and shiny on top. Pale lavender flowers bloom in August.

According to The Hostapedia by Mark Zilis (2009), "...The American Hosta Society registration for 'Lahn'...describes this as a 5" by 10" mound of foliage...producing pure white flowers...'Lahn' actually becomes a larger plant with larger leaves that display 10-12 vein pairs."

This is the name of a river in Germany.