I planted a very small Cottonwood 4 years back. It was just a small twig when I planted it and now it is well over 15' tall. I think it actually grew too fast. I can't seem to keep it upright. I don't know if the roots can't supports it or what but I have tried several different methods to try and keep it upright but it always seems to fall over. It is still growing very well it is just on its side. Is there anything I can do to help this or should I just cut it down and start over? Thanks for any help.