Probably worth noting that the hairs on the plant are semi-stiff and quite irritating.
I planted some in the sandbeds last year and all of these (covered in winter) have survived without rotting in the middle. Perhaps they just need more air movement than they get inside.
If anyone wants to try it from seed, I have lots to spare, just ask. It's not worth sowing it now until next winter (unless you can give it a good freeze!) but old seed seems to germinate well so the delay shouldn't matter much
Paul