When I stuffed dead nettles into an old bottle of Diet Lemonade topped up with water, I expected them to rot down into plant food. But after going cloudy for a month or so the water gradually cleared showing this. Unbeleivable and a candidate for space travel, its created its own environment, in a sealed bottle.
I put Comfrey in a bottle at the same time and it went more smelly and rotted down.
I'd heard Nettles were hardy but this is Bonkers.