Posted: 17/04/2017 at 11:12
The seeds are readily available, germinate and grow quickly and survive OK in some parts of the UK until a really hard winter comes along. I had one for about 8 years, not as as impressive as yours. -14C a few winters ago finished it off. With hindsight I wonder if it might have regrown from the base had I not dug it up
I've now grown another, 2 years from seed, 3 flower heads
Where are you?