I found it takes quite a while for the roots to hold the soil in place. By the end of the summer you'll be able to hang it up. I didn't have too much success with overwintering mine, but if you put it in the corner and put leaves over it it should be fine. Depends on your winter situation.
Here's what my poor mosaic looks like - I took the wire off it, and I'll just replant more chicks as they come available.
