Some have been growing outside here for several decades. I don't do anything to them - they are totally no-care. No dead foliage to remove, no dividing. Every summer, they flower. A friend had lots in pots and took big pots of them in flower to club meetings. I imported some named ones from Ireland and put them in pots. They weren't easy-care in pots, and soon disappeared. There is obviously some skill required which I didn't master. So now I'm happy just to have the ones in the garden. Diane Whitehead Victoria, British Columbia, Canada maritime zone 8, cool Mediterranean climate mild rainy winters, mild dry summers