I've found that this nightbloomer needs even warmer water than the day blooming tropicals. It is starting to slow down here now and it doesn't bloom at all in the coldest month of the year. The coldest the water temps get in my pond is about 74°F and that is generally only the month of Feb depending on when we get those colder nortes. The one I have in the roof pond will bloom all year but slow down in Jan and Feb, that pond is in full sun and isn't as deep as the pond in the yard so the temps stay higher. When the water is in the 90°'s F they bloom like crazy, so I'd say they love hot water.
I've sniffed them and not smelled any scent at all.
