Marc, you make a good point.
I just planted some grocery store burdock, but I do it with the thought it will be there forever.
It is a lot like comfrey but not sterile and that makes it a hazard.
I cut them down and use the leaves as mulch whenever I have time, but I always make time to cut off the flowering heads.
Honestly, I think it could survive being caged with chickens, which comfrey cannot.
Let me pitch another broadleaf plant.
The China Pink, Colocasia esculenta, Elephant Ear.
It <might> be edible.
https://permies.com/t/20858/root-crops/cultivars-Colocasia-esculenta-taro-edible#1601094