I have to deal with it a lot up here, including in heavy black gumbo.
It sends it true roots DEEP, over a foot down. What you are pulling are young roots.
If there is a systemic killer use it; if you do not eventually you will have pull the entire garden and dig it out.
Miss one little section and it comes back quickly.
The old main root is brown. It spreads by seeds and rhizomes.
