This looks to be a variety of (or the same) cut-leafed Hibiscus acetosella that's been around for a long time.

H. acetosella is a great foliage accent plant (flowers are inconspicuous and may appear too late in the season for northern growers), amenable to pruning to maintain size and shape and easily reproducible from cuttings. Give it full sun (I don't know about water culture) and it's easy to grow.