Planting in a city sidewalk is a noble endeavor but almost always a gamble. Between the car doors, peeing dogs, and rambling drunks, these plants endure a constantly threatened existence. Protective sidewalk barriers are often flimsy and get beat up quickly. But build one out of half-inch thick rope and four pieces of rebar, and you have a sturdy, inexpensive, and easy solution. Even better, the plants remain in full view and the design complements the small square landscape.