The Federal Prison on Alcatraz was meant for the ‘worst of the worst’. Inmates only got sent to Alcatraz because they were behaving badly at another prison; in a way, they had to earn their way to Alcatraz.

But what if you are a plant? And you are misbehaving? And you are already on Alcatraz?

This seems to be the case with our Agaves.

While the island was operating as a military fortress to protect the Bay, and later as a military prison, Agave americana were brought to the island in the early 1920s in attempts to landscape the island. The plant proved to be ideal for growing in the dry, rocky soil with little water or care. But this plant has a defense mechanism of its own. Perhaps it is not commonly known, but Agaves can cause skin irritations when the sap comes into contact with people’s skin.

While not everyone is afflicted, a few of my volunteers have had reactions to being poked by the thorns or have developed a skin reaction with itching and blistering because of the sap. The sap contains calcium oxalate crystals, acrid oils, saponins, and other compounds, but it seems the calcium oxalate is responsible for the irritation.

A quick search on Wikipedia found that – “The juice from many species of agave can cause acute contact dermatitis. It will produce reddening and blistering lasting one to two weeks. Episodes of itching may recur up to a year thereafter, even though there is no longer a visible rash. Irritation is, in part, caused by calcium oxalate raphides. Dried parts of the plants can be handled with bare hands with little or no effect. If the skin is pierced deeply enough by the needle-like ends of the leaf from a vigorously growing plant, this can also cause blood vessels in the surrounding area to erupt and an area some 6–7 cm across appear to be bruised. This may last up to two to three weeks.”

There are three types of Agaves on the

Agave attenuata has smooth leaves and no thorns. Photo by Shelagh Fritz

island – Agave americana, which has established itself on hillsides and needs minimal care, while in the gardens, we have introduced Agave attenuata and Agave parryi. The Agave attenuata is my favorite! Not surprisingly, it has smooth leaves and no thorns. The Agave parryi, has a different story. This low growing blue leaved succulent has black spines along the margins of the leaves and the tip – very nice to look at, but not nice to weed around.

Agave parryi

Like a bad sibling, this plant has been cursed at more often than any other plant on the island, and is one step away from the compost pile after pricking the volunteer that stewards the succulent slope. Instead of being sent to ‘D’ Block aka, the compost pile, Agave parryi will be isolated on a slope outside of the rec yard, far away from any well-meaning hands. With a view of the Golden Gate and city, Agave parryi, can think long and hard about what it has done! Or perhaps, it will think ‘alone at last, now I can enjoy the view’.

The view from the ‘bad plant’ corner. Photo by Shelagh Fritz