Can I plant my aquatic plant in sand?

I have a Carolina Fanwort or Tropical Hanwort (Im not sure mine is which) and it doesn't have roots and my filtration pump is powerful and I have a small tank. I am thinking of planting it in sand ( I saw some in the fish pet store ) but I don't know if its ok. And I also have another similar aquatic plant that looks like them but its leaves doesn't grow out too big and has roots growing out from its stem that has needle leaves. How can I plant these plants in my tank that has a powerful filtration pump? And is sand suitable for some of my fish? I'll put a layer of gravel on top of the sand because I have 3 plecos.