Are these plants or weeds?

Try the old trick of putting some Glyphosphate in a polythene bag and stuffing the leaves/growth into it. I would also scrape/scar it a bit in case it helps the absorption. If the bag it sellotaped up, the growth will remain in contact with the weedkiller for several days or weeks.

 

I think it looks like my anemone also - I would keep it