With pointy, treacherous, dagger-like leaves and toxic juices,the agave is Mother Nature's barbed-wire fence. At Alcatraz, the agaves were planted in the early 1900s to prevent erosion, beautify the island and deter potential escapees. There are four different species on the island, with the most prevalent being the Agave americana. Like all agaves, it has shallow roots ideal for rocky soil, a rosette of thick, fleshy leaves and a flowering stalk that can grow up to 40 feet. And inside, running through it, is a raw sap that's toxic. These same plants have become the centerpiece for a masterful vision built of stone and exotic plants. It's the agave trail, a stone-lined path that crisscrosses the southern island edge. The goal of the agave trail was to create views--a place where people could see how the island sits within the bay and to see the tidal pools and nearby gardens.
One of the biggest challenges in creating the trail was simply moving materials. Thousands of tons of stone, mortar, concrete and gravel were brought over on barges as big as football fields. The largest mounted crane on the West Coast was used to lift the concrete trucks.
The agave trail was completed in 1994, and it serves the gardens well. Visitors have access to an area of the island that wasn't accessible, and they can also enjoy glorious views of the San Francisco Bay.