Posted: 31/08/2012 at 06:20
Roundup should kill them if you spray it on the young growth in the spring.Follow the dilution rates on the label.You need to leave it on three weeks for the spray to translocate from the leaves down to the roots.I was given a large old Hydrangea a few years ago, complete with large old bramble growing through the middle of it,I cut each stem and applied neat Roundup with a small paint brush to the end of each cut stem and just left it,being very careful not to drip any onto the Hydrangea.
It worked a treat,just be sure to leave it and not cut off the top growth for three weeks. Good luck with whatever method you use and don't eat any of the berries if any should survive.I remember being told that Roundup dous 'nt stay in the ground, but not not convinced.
Good Luck