I did it again, went to get some forest bathing and I ended up doing about an hour and a half of digging up knotweeds. I found some good sized root balls and more large roots close to where I found that other one. I just happened to spot what I call a "cluster" of shoots which usually means they're attached to a root ball. I dug up a couple of them.
This is what the cluster looks like on the surface.
The first root ball after I pried it up.
The second rootball.
