Very easy. I took some seed from the flower (shiny black almost beetle like) in autumn and planted in a window box. By April I had a window box full of red grass like seedlings. Very hardy. Negative is mine are now 4 years old and are about 20cm tall - so they are slow to grow. Not sure if they come true from seed either.

Dividing is easy, as they clump and easy to pick apart.

I did the same except my seed came from a seed pod I saw in a London Park. It did flower after 10yrs and it split easily. I eventually dug it out , potted it on and sold it at a charity fair.

A named variety wont come true from seed.

Yup. As others say, dead easy. Too easy if you don't want extra after flowering/self seeding so unless you garden like me, dead head. Supposed to be only USDA zones 8 and above but mine were fine after UK's horrible winter of 2010/11, unlike the cordylines. I lost loads of those.

Thank you for that, everyone. I've lost enough cordylines never to bother again, Sarra - they just don't survive our mountain winters, even in sheltered spots! Bearing in mind the slow growth, Kildermorie, I think I may well go for established plants, if I can get them: seed propagation sounds a bit on the slow side.

If I may suggest Gattina to get 3. One green, one variegated and one of the red or blacks. They do look smart when planted in 3's.

That sounds like a splendid idea, Kildermorie, I just hope I have enough space! I was hoping to plant them in containers. Our soil here is a bit shallow, and in parts, the mountain pokes through, so I tend to have a lot of stuff in tubs.

You may find you need to cover them for the winter with fleece or something similar. They don't like moisture getting into the crowns and then freezing.

http://www.growsonyou.com/photo/slideshow/263755-phormiums-st-andrews/member/kildermorie

I have been collecting plating ideas and took this of some phormium a few weeks ago.

I've just had a look - lovely specimens, K.