This cultivar is a hybrid of H. 'Invincible'
and H. 'Northern Halo' which was registered by
Greg Johnson in
2004. It forms a large (20 inches high) mound of blue foliage
and has very pale bluish white flowers in August.
The Hostapedia by
(2009), "It is widely considered to be the earliest
blooming, fragrant-flowered hosta."
The Hosta Journal, Vol. 31, No 1, page 91, states that H. 'Moonlight
Sonata' is the earliest blooming of the fragrant hostas.