How to kill bracken ferns
The bracken fern, also called Pteridium aquilinum, is a perennial plant that can reach heights of between 45 cm and 2 m (1 1/2 and 6 1/2 feet). While the plant is a hardy species that is a good ground cover, its hardiness also makes it invasive in many areas.
To successfully eliminate the bracken fern, chemical control methods are typically used to kill the deep, underground tap root.
Wait until summer and set the mowing height on a lawnmower to between 7.5 and 10 cm (3 and 4 inches) high. Attach a grass catcher to the lawnmower and mow the entire area where the bracken ferns are growing to cut off the spores. When you are finished, empty the grass catcher clippings into a bin bag and dispose of it.
Fill a garden sprayer with an herbicide containing the ingredient dicamba or glyphosate. If there is surrounding vegetation that you want to keep, use dicamba, otherwise, use glyphosate.
Add in the amount of water as directed by the herbicide packaging and then close the sprayer. Shake the sprayer to mix the contents.
Spray the bracken ferns with the herbicide until the solution drips off of the stems and fronds.
Wait until the late winter and apply another dose of the herbicide spray in the same manner to prevent any remaining bracken fern root systems from regrowing in the spring.