A Port Townsend resident moved into a house less than a year ago where the yard had been neglected, and noticed a lot of brown bracken fern. She pulled/dug it up. However this spring it is coming up all over the place and she wants to know more about it and the best way to approach this invasive plant.
We discussed the following:
Bracken fern spreads via underground rhizomes that can grow 20 feet long and ten feet deep. So pulling and digging is not going to remove all of it and it will regenerate. It is deciduous and dies back after frost but reemerges in spring. Bracken fern also releases spores from the undersides of its fronds (pinnae) in later summer/fall.
If a yard is already densely vegetated, bracken fern will have a harder time getting established. Once it is established it suppresses (chemically) the growth of other species.
Herbicide is not recommended so assertive persistent management is the best option. Cutting in early summer will deplete it, and cutting it again when it regrows will deplete again. Cutting/mowing/pulling will also reduce spore production.
Bracken fern is poisonous to horses and sheep although native peoples ate the fiddleheads and people today do, too. However bracken fiddleheads have been shown to be carcinogenic if too many are eaten.
Basically, she has her work cut out for her during the next couple of years. With persistence she will get the upper hand.