I just started my first garden

[img]https://i647.photobucket.com/albums/uu195/kohleryan/GardenProblem01.jpg[/img]
This plant has a large, but weak root system. I have tried to remove as much of the root system as possible, but it is very difficult because it breaks apart so easily.
Does anyone know this plant? How concerned should I be about making sure all of the old roots are gone? I plan on planting a vegetable and herb garden.
Thank you!
