How to kill the leylandii

Leylandii is a cypress that grows too fast and too tall.  There have been murders over this matter, neighbors lose their temper over the giant plants, cut them down, then a spiral of reprisals, often violence.  A plague of aphids -flying angels- has come from the Mediterranean to stop the plague of leylandii that blights the British islands.
The best way to attract the aphids is to spray a sugar solution on the leaves, on your side of the hedge, when no one is looking. Aphids fly about and they will feed on the sugary solution and then on the leaves of the plant.  If the monster plant is not readily accessible, it doesn’t matter.  Plant yourself one or two small ones, or cypresses of any kind. Spray them with the sugar solution. The angels will alight on them, feed and then move on, to the big curtain of green food near by.