Raised beds separate the spikey plants from the pathway.

A Manual for the Design and Implementation of Teaching and Demonstration Gardens

Teaching and demonstration gardens are places where the public can learn about different types of gardens and landscapes.  This 10-page fact sheet discusses the various types of gardens, how to plan and develop a demonstration garden, logistical and design considerations, and educational programming. Written by Gail Hansen and published by the UF Environmental Horticulture Department, July 2015.
http://edis.ifas.ufl.edu/ep524