When I eradicate a blackberry patch, I, first, mow them down to the
ground. Then, when the sprouts are 4" to 6" tall, I give them a good dose
of Round-Up. I usually need to repeat that two to three times then wait a
season to be sure I killed them all. I must keep after them because if I
allow too much time between spraying, they become resistant to Round-Up
necessitating more drastic measures.
--
Jim Fruth
Brambleberry Farm
Pequot Lakes, MN
www.bberryfarm.com
Jams, Jellies and Syrups
We have some blackberries that just wont seem to die here in Zone 4/5 of
northern Illinois. They have been plowed under at leat 4 times, raspberries
planted in their place, and they still came back and overtook the
raspberries.
Dennis Norton
[NAFEX] Eradicating Blackberry Plants,
Jim Fruth, 12/17/2005