Can't say l've heard of this before @ERICS MUM. Any chance of a photo? I know they need deadheading otherwise they set seed everywhere but l don't know if the leaves collapse if this isn't done due to the weight of the plant.
The seed pods make the plant very top heavy so need to be dead headed to stop them them flopping over and to stop self seeding as already mentioned. The leaves on mine are fine, I am assuming they just die back and re emerge next year but I am not really sure.
Posts
https://www.burncoose.co.uk/site/plants.cfm?pl_id=3960
thanks
I know they need deadheading otherwise they set seed everywhere but l don't know if the leaves collapse if this isn't done due to the weight of the plant.