Japanese Barberry is an invasive shrub that grows heavily along some of our trails. It nasty, has lots of thorns, doesn't die easily, harbors ticks, crowds out native plants and wildflowers. In short, not nice to have in town parks and on trails.
The Connecticut Agricultural Experimental Station has a booklet on ways to remove barberry titled "Japanese Barberry Control Methods". Methods including pulling, cutting, burning, and using herbicides on the plants. Each method has their pluses and minuses, and will probably need to be repeated to be effective.
There are also a series of videos on You Tube from the UConn Extension Office regarding ways to control barberry. There are 3 videos that give an overview of barberry and Lyme Disease. Part 2 covers ways to control or eliminate barberry.
We had an earlier blog post in 2011 about Burning Barberry. We had some success, but it's a stubborn plant to remove. One option is to pull it up and dispose of it so it can't reroot itself back into the ground. Some can be pulled up easily by hand early in the spring. Larger clumps may be removed with a weed wrench; a heavy crowbar-like pry bar with a clamping foot that can grip the stem and pull the whole thing out. Ours is from the Puller Bear Company in Canada.
Other methods including cutting; either manually with long handled loppers, or with a hand held brushcutter like the one below.