Janet Baraclough wrote:
This elegant blue-green serrated foliage plant is well established in
the front garden now, in a sunny spot between big boulders; it flowers
but not well enough to set seed. I'd like to propagate it to use in
another part of the garden, does anyone have experience of doing this?

Janet, this forms a sizeable, woody rootstock and as you are probably
aware, it acts as an herbaceous plant in cold winter regions. It can
be propped from tip cuttings taken in summer, but can also be divided
as you would a Delphinium or Aster. The only difference is that you
will need to saw through the roots, making sure each piece has at least
some top growth. Mid spring is the best time to do this.