Sorry if this has been asked before - I couldn't get the search function to find anything and googling "spiky dandelion" just gets me lots of pictures of dandelion seeds.

I have these plants growing in my front yard, over where a tree was cut down about three years ago. They're a pain to try to get rid of because of the spikes and their root systems. Unlike dandelions, they don't have a single taproot going straight down. The seem to have thick runners about 5-7 inches under the ground, so it's almost impossible to get the root out (did I mention the tree that used to be in that area? There's still tree roots that make digging out weeds difficult).

Any advice on what these are and how to keep them from returning would be greatly appreciated.

Thanks!

Jeremie.

Image link: