Although in many parts of the country, blackberries are grown for their juicy, sweet and tart summer fruit, in some parts of the United States blackberry brambles are treated as an invasive nuisance. The invasive species of blackberry are primarily the Himalayan and evergreen blackberry varieties. And while some farmers treat thickets of blackberries with broad-spectrum herbicides, others worry about the effects on the environment. Although it takes a lot of work, blackberries can be controlled by manual means. The secret is to remove the roots to prevent the brambles from returning.
Mow berry brambles down to the ground before the plants have a chance to produce berries. Unless you remove berry plants before this point, the brambles may be spread by birds through seeds, or the tips may root where they touch the ground.
Dig up the roots of berries with shovels, hoes and rakes. Blackberry brambles often emerge from root points known as nodes. Removing the nodes will prevent the brambles from reoccurring.
Watch the location of former berry thickets for re-emerging blackberry shoots. The shoots look like miniature blackberry canes, with clusters of three leaves and bright green thorns.
Follow the shoots of blackberries back to the ground to locate the nodes. Dig up these nodes and discard the shoots and nodes.