moved in october to a new house and finally got round to emptying the garden of mainly ivy growing over 3ft high walls.

the issue is the roots have grown in three seperate places underneath walls (some of which ajoin neighbours garden) and i can't comnpltely remove them. I've cut down as much as i can reach, but as i'm not going to get round to putting raised beds over these remaining roots for a month or so and i'm wondering what the best way is to stop the roots from re-growing both now and for good.

i want to avoid putting down poison as it may damage an old beautiful plum tree which was the only thing worth saving so any advice would be greatly appreciated. if u need any more info just ask, cheers