It can get quite wide as it gets older, it depends on if you want it touching the house or not. 2 metres or so.
Carol ... have you seen Banana Joe's Dicksonia? It's nestled in a fairly tight spot but has emmense fronds. I think they gotta be 8 feet long anyway. A real nice specimen that he's had planted for quite some time. Cheers, LPN (Barrie)
True, Joes is a beautiful one, but I like the idea that a plant can have the extra space to stretch out and not touch the house. Gives it a more distinct look.