Plant anchors are the way to go...but I have this on my mind so I'll just spit it out.
Someone I know from another forum takes little tupperware containers, fills them with a plant substrate, cuts holes in the lid (for the plant stalks and smaller ones for water movement), feeds the plant through, and buries the container. this keeps the plant in place. It also works for those who dont want to rip out their whole substrate but want to try a rootfeeding plant or two.
But yah, rocks or plant anchors are best lol