Here’s an illustration of what can happen even to an experienced turner:
This is from a conifer, not Leylandii, but out of the same family. It was given to me by a neighbour. The wood is very soft, so much so that a shear scrape produced a very rough surface, which looked almost like the wood had been brushed with a heavy steel brush.
Instead of trying to get a smooth finish, I decided to leave it this way, maybe scorch it later with a blowtorch, and see what would come out of it.
Drilled a hole down the centre and started hollowing. This is where the softness of the wood became a problem. When I was down to about a 1/4″ wall thickness , small cracks started to appear. And when I made a small mistake and the backside of my hollowing tool touched the opposing inside wall, the tool started to rattle around, and within less than 2 seconds it was all over.