Hi, yes they are deep rooted, but you answered your own question, just go down as far as you can, a few roots left in the ground wont do any harm, but it,s hard work. regards derekm.

Thanks for your answer but having read some other comments on cordylines, it seems that the roots can sprout again which I really don't want! Do you suggest any kind of root 'killer' to stop this happening?

Hi, s b g is a good root killer, but I have never heard of them growing back from just the root?
good luck, regards derekm

Thanks again - will try it out! I must have misunderstood, maybe it was the stump that grew back?

Again, thanks for your help
Lucie

Hi, yes they can grow back from the stump if the top growth is damaged,ie frost, which has killed off a lot this year, but a lot have sent shoots out from either lower down the trunk, or from the base. regards derekm

Leaving a few bits of fibrous roots at the bottom should be fine - get out all the stump and as much root material as you can though, or there's a chance they'll regrow. I think Derekm meant SBK when he said SBG, but that won't be too much use to you - its used on stumps which have been cut to the ground as a means of poisoning to stop them regrowing, usually on deciduous trees where the stump will remain in the ground. Cordylines have a different structure, so killing off the main stem wouldn't necessarily prevent regrowth off to one side.