Comfrey

Um - not sure - but best be on the safe side. See what others say. As for "pant food" - maybe someone will "nickit" 

They look like the white growth on squash and courgettes later in the season

I take comfrey as a special weed, and don't really worry about what it looks like, Lils!

All ours is safely chopped down and in two plastic containers with a little water, and we'll just tip it all into a bigger water butt and use it every week!

I really need some more nettles now, as they go in as well...