Our house is on a corner. At the side of the garden is a privit hedge,
and at the end is a stone wall. The corner where the two meet is very
vulnerable to burglars, and there've recently been 3 in the street.

So... we need either barbed wire (joking) or a nice thorny bush to
make that access route less attractive.
We have a thorny bush elsewhere in the garden. The leaves are red on
one side. It'd look nice against the green privit. What is it?
What alternative bushes would do the trick?
Is it a good time to plant?

Thanks

Tony