Hi to anyone reading this. I live in ne. Ive been trying to kill ferns. Why? They have spread like wild fire. Five & ahalf ft. tall. Now in the sun and look awful by July. Tried roundup after I pulled off leaves last year. Should have left leaves on? Their still growin! Now Im digging! oh my! Runners are everywhere, 6-12" underground. Im not young enough anymore for this brutal digging.
Roundup is only absorbed by fresh, green leaves. Spraying Roundup on dead leaves or on the ground is ineffective as it will never be absorbed by the plant. It should really be used on vigorously growing plants in the spring or summer.
Or weedeat them to about 3-4 inches tall then Round-Up them. The left over stalks from the weedeating will absorb the Round-Up in a hurry. I do this frequently on brushy material and it works quite well.
Resin, do Bracken ferns get that tall? Mine only get to about 2-2.5 feet. I was thinking more along the lines of Ostrich ferns as they spread quite readily too.