Please identify this alien beast & the weapon to destroy it!
This plant grew in a sunny bed that we cleared that had a covering of English ivy two summers ago. Initially I thought there were stones in the soil at shovel level but found that actually this was a root of a plant had fibrous,thick roots that were sometimes the thickness of fireplace wood! These plants grow as tall as several feet if left unmoved. The sprouts are reddish with white stems when newly growing from the dirt. Last year we weeded and dug down 1.5 feet and pulled out tons of the woody roots and laid down cardboard and mulch over, thinking we had done a thorough job getting rid of this nasty stuff. Well 4 weeks late the stuff started sprouting up again. Our work seems to have encouraged it. I am pretty adverse to chemicals. Will black plastic over the bed do it? Any thoughts on what it is and a good way to eradicate it? Thanks in advance!