Some suggestions...

1. Kew gardens gives it nice cane wigwams to clamber up and then sprays the
wigwams.
2. I've heard that autumn is the best "attack" time as the plant is starting
to draw down sap into the roots, taking the "killer" with it.
3. Buy good rubber gloves, over these place cotton gloves, dunk your hands
in "killer" and then lovingly stroke the leaves - honest!

Alternatively, eternal vigilence and tear it out. Our garden it not totally
free but we don't ever use chemicals.

Paul "I can't spell glyco-whatsit" DS.