I have this bamboo in my 100g tank. When I bought the bamboo 3 months ago, I cut them all just below the water line. The ones that have not grown above the water line seem to be growing moldy or have an algae accumulation, but the others than grew out of the water look far better. Roots are just hair-like structures and spread out in my sand substrate. BTW, even the clippings can be planted and will grow roots as well.