I accidentially transported a piece less than 6 inches long into my yard when I rescued an azalea. The first year that fern slept while it built up strength. The next year, it popped up in a few places and by the next year it was yards away from the original spot.

I am in North Georgia and I consider it aggressive, especially in good garden soil.

I would not!! I planted several specimens in two areas of my yard about three years ago, and I am now trying to dig the widespread system of rhizomes out of other plants, etc. It has become a total nuisance, and I regret having transplanted it. It travels for yards underground, and then pops up in the middle of other plants, requiring that they be uprooted, etc. Leave it where it is!!

Well I put some bracken(Pteridium aqulilinum) in my moms garden and it nevr spread, but then it was in poor heavy soil.

after a nuclear holocaust there will three things left. Joan Collins, cockroaches and bracken

It was native to my property and I generally tolerate it, pulling it up when it invades my paths or gets out of bounds. At least bracken in the states is more refined than that in Britain.

It grows wild in my yard as well, so I also leave it, but I don't think I would introduce it unless you had the space for it.

If you live in fire prone areas, it is also a fire hazard when it colonizes. It actually thrives in fire prone areas. The dry fronds catch easily while the underground roots survive and actually spread more readily after a fire. I would guess this helps stabilize soils afterwards.

An interesting, if aggressive plant.

Jeanne