Posted: 28/10/2016 at 09:23
I live in Devon and I left them in the ground last year.
I cut them down after the first frost , mulched the bed with well rotted leaf mouldy and then covered with garden fleece . They were fine and even stronger in growth than previous years when I have lifted.
they are in a well draining bed but I do live on the edge of Dartmoor so the weather can be quite severe.