If this plant info box on watering; zones; height; etc. is mostly empty you can click on the edit tab and fill in the blanks!
Standard Cyclopedia of Horticulture
Nuphar japonicum, DC. Similar to the last. Submerged Lvs. large, crisped: fl. 2-3 in. across: fr. flask-shaped. Japan. —A form with red-tipped stamens and sepals is cult.
The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.