I'm thinking this is a weed. It's growing in one part of my backyard. Its really hard to uproot the plant. The root is thick and even the small plants grow off of the left over root in the ground. If I try to pull it with bare hands, the core of the stem stays only the outer cover with the leaves come off. Its slippery too. Has anyone seen this and know how to get rid of it?
EDIT: I live in the pacific northwest near Seattle.