This is a really cool plant, literally! I've seen it blooming under the ice in Kansas! Water Hawthorne is native to South Africa where it grows during the cool winter months in vernal ponds. A vernal pond fills up in the wet season and dries up in the dry season.
To grow this plant successfully you must imitate it's natural growth habit by putting it into your pond in November. There it will grow and bloom until May. Take it out and put it; pot, plant and all in your garage and DON'T WATER IT! Let it dry out completely, then in November back into the pond it goes to start the cycle all over again. To see a picture of Water Hawthorne click here.