Killing Leylandii Roots

A neighbour is cutting down her hedge of Leylandii.
Someone already pruned it to 4' from 12'+ and the centre 2' is dead although 6" each side is thriving.

What is the best poison to kill the root? Digging up could be an issue due to Block paving.

 

Hi

Leylandii doest re-grow back from its roots the only good thing this conifer has to offer, so dont waste your money on "poison", getting the roots out will be orrid if in the way

Spruce

 

If the stumps are being taken out gcc just cut the roots away and they will perish in time.

 

I have a Leylandii stump left behind where one was removed to create a path to a side gate. It was cut flush with the ground, more than 7 years ago, and it still a shiny death-slip when wet ... so you might want to pro-actively do something.

Can you get a stump grinder in?

 

It looks like a drill and tar scenario then - unless a better rotting medium is known

 

I do believe there is a commercial product ... can't remember the name though. Diesel and the like is often touted, but it doesn't do the soil any good ... some sort of material that would soak in and then allow you to burn the stumps out any good?

Mine you ... we piled up our stumps (dug out with a JCB), and it took several goes to burn them at the end of bone-dry Summer periods and staked high with hedge cuttings etc. to provide some "fuel" ... not sure an underground fire will burn all that readily, and if you don't get rid of them properly the ground will, presumably?, sink as the wood rots

 

Hire a stump grinder for the day that will slice through the roots I was watching beechgrove last night they had one on the show, my favourite gardening programe.

Spruce

 

There is/was a commercial product "stump out" or something like that - drill into the stumps, pour it in and in a year or so they rot. I used it on a big flowering cherry to good effect, but it did take two or three years.
The roots of Leylandii will rot (more so than the stumps) but it takes several years. We cut down a hedge about ten years ago and are only now able to lift the stumps with relative ease.