Comfrey is a beautiful broadleaf herbal plant, which in the right setting can be very attractive. However, in my semi shade garden, it has taken over. It obscures the light from my flowering plants, and has such deep roots, it has been nearly impossible to eradicate. I pull it, it comes back. I dig it out by the roots, the broken root comes back. I have even resorted to Roundup and garden fabric, and it comes back! Someone said, just break the leaves off and don't disturb it's soil, as that will break the roots and it will come back tenfold. It did! Last year, I even cut the leaves up and composted them because they are supposed to have a lot of nutrients, but I am afraid of putting that stuff in my garden in case it spreads it more. Help!