PlantFiles: Yellow Waterlily
Nuphar polysepalum

Large, fat, air-ridden rhizomes creep a foot or so a year when happy. Heavy bricks or rock will be needed to keep it pinned to the bottom until it anchors itself. Blooms in July in the mountains. Leaves are larger and more rounded than other Nuphar.

Lovely plant- if your temperature does not exceed 75 degrees. That is when the poor thing suffers. It is native to alpine ponds with a humusy pine-needle bottom; that is the only place I have ever observed them naturally. Does well in places with cool summers. Also requires richer soil than Nymphaea.

A very-cold-climate person could still have a waterlily in his pond, thanks to this plant (Since he could kiss his Nymphaea goodbye in winter or summer).