I put one in the ground some years ago in the back corner of my yard, Ibis, and it HAS taken over that corner. Not as quickly as some of the other ferns, but it has spread. I also have one in a big pot in my front yard and recently saw that it too has spread into the ground and around the pot. It's not fast enough to get away from you, but I wouldn't ignore it for 3 years either! Hope that helps!
