I have used some 'Roundup brush killer' before in a Glad bag rubber banded to a wad of leaves so that they soak in it.
Just where rubber gloves and grab a limb full of leaves and dunk then into the Glad bag, fill it with enough full strentgh Roundup, then use rubber bands to attach the bag. It will take awhile but will eventually suck in enough to kill it all the way to the roots.
Heard it on KTRH Garden Line out of Houston Texas about 25 years ago and have tried it several time with success.