I am a high school volunteer that has created a 75x10 foot flower garden along a public walkway at the school. While the teenagers are respectful of the garden and stay out of it, during the summer, the school's pool is open to the public, and people have to walk by the garden to reach the pool. Unfortunately there have been several instances of plants trampled, pulled up and discarded, and once a trellis attached to the fence that backs the flower bed was stolen. The nearby (but harder to get to) school vegetable garden is surrounded by a low rail fence, and I am thinking of doing the same to the flower garden. I'm hoping it would provide some continuity between the areas, and hopefully discourage casual vandalism. There are some donated used 4x4's and 2x6's I can use to do this. I'm wondering if there is some sort of rule of thumb about how tall a fence needs to be to create the sense of protection and "hands off", yet still allow people to look easily at the flowers, and appear gracious at the same time. Would any of you landscape professionals have an idea of what would work best? Thanks, Sue