I have grown it from seed, but not deliberately - they were self set, I found them the following year after the parent plant had died, so apparently, they don't need any special treatment! My book, though, says to sow seed in Spring in a cold frame.

thanks bamboo i have had self-sown seedlings as well this year, so i guess it is worth the risk. i have found a mixed herbacous packet and a succulent mixed pack too. thanks again.