Q: Are the prickly stems sharp and dangerous for kiddies or just knobbly and hard ?
Q: What's your biggest height / width / leaf ?
Q: Can anyone advise in what ways tinctoria is different from manicata ? I know it's smaller (all dimensions) but are the leaves as interesting / any less prickly... does it still look insane or rather tame ?
Actually they are hardy - in that the root system stays alive over Winter, but frosts tend to kill off the leaves / stems and reduce them to brown mush. The crowns need protecting with straw / bark / old leaves etc. but should come back year after year no prob.
After the last frost, they'll be nothing to stop them !