It depends on how old the roots are in the ground. Take what is there now before it freezes...............clean up the ferns...............mulch the ground 2 to 4 inches on top.......................1st year roots............don't pick, 2nd year roots..........pick some.......3rd year pick 8 to 10 weeks.............then clean it off............
I don't know exactly where you fall into the root years.........we have to cover ours in hay for the winter as this is 5a and they will freeze.