By Dianna
Victoria,
Australia 
We have had a big clump of cordylines in an area about 1/2m wide and 1.2m long, between a high right angled 3 layer brick wall and a concrete pool. The cordylines have cracked the brick wall (now being replaced at great expense) and although we have dug out many of the old roots, new plants keep appearing. I have been cutting these and painting them with concentrated Round-up but as fast as I poison them, new shoots appear. How can I rid myself of these damaging plants quickly and permanently?
Dianna
Melbourne
18 Apr, 2010
You need a brushwood killer - funnily enough, it would have been easier to kill the roots if you'd left the main stumps in place. Over here I'd recommend SBK, but you will need to find the Ozzie equivalent. Drill into or make cuts in any roots you find and apply the brushwood killer, cover and leave. If you excavate soil to get at the roots (and you probably need to), cover what you've applied before replacing the soil.
18 Apr, 2010