Q.Cordyline root heave
Cordyline planted beside pavement has many sprouts and has cause significant root heave. So much so it has started pulling up pavement. Gardener suggested cutting it down and killing it however it is still sprouting. I know it needs dug out my question is how big a job will this likely be please?
This job is best done by a stump grinding service. To do a thorough job you need to remove and replace the asphalt pavement and the headerboard in the vicinity of the stump. A stump grinding machine can then access the stump and grind it to below ground level, chipping the entire wood mass to about one foot below grade. It then has to be backfilled with imported soil, the grindings hauled away or dispersed in your garden somewhere. The headerboard and asphalt have to be replaced to finish the job.
To do it yourself or have the gardener do it is a big job with pick and shovel and maybe a rented stump grinder if available. The extent of the wood mass of the root crown below grade remains to be seen when you get into it. It could be very tough to get through and get it all out.
The alternative is to do nothing except maybe poison the stump with herbicide to prevent resprouting. But if you don't want to do that, just keep cutting off the new sprouts that come up and eventually the stump will die from lack of photosynthesis of sugars to keep the roots alive.