Burdock - cultivated as a vegetable in Japan where it is known as gobo. The stalks are scraped and cooked like celery. The roots can be eaten raw in salads or added to stir fries.
Kudzu - AKA Japanese arrowroot. It is a prolific weed in south Florida. A starch can be made from its roots. This starch can be used to thicken sauces and gravies as you would use cornstarch. The leaves can be battered and fried.
I knew kudzu would pop up on this thread.