In article , John
McMillan writes

There's a real gap in the market for a book titled "Security Plantings",
describing all the spiny thicket forming plants which are actually
in some other way horticulturally attractive. It would have a section
on screens and possibly a (very thin) section on attempts at cat-proofing.

Talk to your local policy security advisor - at least one police force
gives out a leaflet describing different plants for security hedging.
--
Kay
"Do not insult the crocodile until you have crossed the river"