The website I purchased my American Frogbit (Limnobium Spongia) from says one can choose either free floating or planting in small containers with the roots in soil and placed with 2 inches of water over pots. My pond shelves are 10" deep and sometimes on Mondays after I am gone a whole weekend, the water level can have dropped by 3 inches. I had one planted and under 2" of water as instructed, but it died when the water level dropped below the top of the pot. Can I plant them deeper than 2 inches below the water? Like more like 5-6" below the water, so when the water level drops, they are still under water? Or will they not grow if that deep? I have the rest all floating now, but I read that if they are planted underwater they will grow more upright with the leaves sticking up out of the water and look different, and since I have 6 of them, it would be nice to have at least one look a little different.