Instructions. Plant thick and prickly shrubs surrounding the perimeter of the walls to make them less accessible. Good choices include rose and hawthorn bushes. Paint the wall with anti-climbing paint. Check with your local council to determine the legal restrictions of using anti-climbing paint.Anti-climbing paint leaves an oily and slippery surface on the wall that is extremely difficult to climb. Add barbed wire or anti-climbing spikes to the upper ledge of the wall to discourage climbers.Anti-climbing spikes are attached to the top of a wall using cement.nstructions. Plant thick and prickly shrubs surrounding the perimeter of the walls to make them less accessible. Good choices include rose and hawthorn bushes. Paint the wall with anti-climbing paint. Check with your local council to determine the legal restrictions of using anti-climbing paint.