I spent weeks earlier in the year cutting ivy from around the base of a lovely hawthorn tree. I've cut back to about 12" from the ground all around. I have since bought some deep root killer hoping to finish the job, but on reading the instructions realise it will be impossible to apply without contaminating the hawthorn. Has anyone got any tips on how to deal with it? There are about 8 ivy stems varying in thichness from 1 1/2 - 5 " in diameter and they completely surround the tree.

Thanks