One of the weeds some love and some hate, Curly Dock aka Rumex Crispus, has a long tap root and can reach heights of 5 feet.
The young leaves are gender and non-toxic for most people, and can be used as a salad green. The seeds are highly nutritious and make great crackers, a nice complement to soft cheeses.
I wrote an article for Triond about this plant: Buckwheat's Cousins