I find this plant hardy, having come through two snowy winters. A frost will cut it to the ground but it comes up again in the spring. It may be better with some shelter under a canopy of trees in a south facing bed, though I have it in both North facing and South facing beds opposite each other.
Left in the ground and not cut back by the frost, it will make a plant of about eight feet with flower spikes about twelve to fourteen feet from the ground to the top, that is , if it has to reach for the light.
Each flower spike should give up about twenty seeds, though they have little seed capsules that make you think you are going to get a couple of hundred. I don't know if it is because the seeds don't set easily, or because the insects over here don't know what the plant is?
Peter
