Hans,
A very beautiful plant. I like the cleanliness of the foliage and the reddish stems and petioles. Maybe crossing it with russoi would produce some stunning smaller cultivars with clean, glossy leaves?
My only hybrid I've produced is three plants of a cross with "japonica alba" as the seed parent and mairei as the pollen parent. They are intermediate, but with the overall look of japonica and pale pink early flowers before the leaves have matured. They also have the rhizomatous habit and tendency to not flower that well like mairei.
