I tie mine to 2x2" cut stainless steel mesh. Han (aka: h4n) with Han Aquatics sells good quality SS mesh by the roll or pre-cut that works perfectly and won't rust.
You can plant it anywhere. Just make sure it's securely anchored or else it won't grow well. Some leftovers I have that initially came on some stainless steel mesh is now growing quickly on it in a holding tank.