Category Archives: Sustainability

Gardening with non-Natives

Earth Day typically involve activities that focus on native plants and restoring habitats, but the day was also an opportunity to demonstrate that gardeners can landscape with drought tolerant non-native plants that are not invasive. Hosting a garden table with Alcatraz Cruises’ Earth Day celebration last week was a chance to highlight plants growing on Alcatraz, that while not native, are extremely well suited to the climate they have been thriving in.


From over 200 species of plants that survived the closure of the prison five plants were chosen to be on display. Each of the five plants has different adaptions to coping with drought, wind, poor soil and sun exposure.


The first plant always receives a lot of attention – Aeonium arboreum, or hens and chicks as most people call it. This succulent is able to store water in its fleshy leaves, and will drop the lower leaves when water becomes scarce. Producing few seeds, the plant mainly propagates itself by the forming roots along its stem. The roots will grow downwards, seeking any soil to root into. The plant is able to thrive in poor soil; I have even seen a massive clump of aeonium growing out of 5 inches of debris that had accumulated on top of a tunnel entrance.


Hens and Chicks. Photo by Shelagh Fritz

Hens and Chicks. Photo by Shelagh Fritz

Another popular succulent is Persian carpet. This little beauty is coloring the hillsides of the island pink right now. As tiny as the leaves are, they store water and the slightly dimpled leaves reflect light. The ice plant is great for stabilizing poor soils. Although an ice plant, this little guy is not the common invasive ice plant that is often seen along freeways.


Nasturtium poking through Persian carpet. Photo by Shelagh Fritz

Nasturtium poking through Persian carpet. Photo by Shelagh Fritz

A common garden plant in the 1940s and 50s was Pelargoniums, commonly known as geraniums. Pelargoniums are from the Southern Hemisphere and are from the

Pelargonium quercifolium - Oak leaf geranium. The leaves have a unique fragrance and are slightly sticky. Photo by Shelagh Fritz

Pelargonium quercifolium – Oak leaf geranium. The leaves have a unique fragrance and are slightly sticky. Photo by Shelagh Fritz

Mediterranean regions of South Africa. Five different cultivars survived on the island. The rough leaves reflect light, as well as the plant will drop its lower leaves when stressed by drought. It is not known exactly how, but the scented leaves of pelargonium are thought to be a survival mechanism.


Another survivor is the common garden nasturtium. It is surprising that the fleshy green round leaves are able to cope with the strong winds and lack of water, but these annuals have been self-seeding since they were introduced in 1924. They are able to complete their life cycle by the time water is becoming scarce in the soil.


Many visitors are surprised to see Calla lilies

Calla lily. Photo by Shelagh Fritz.

Calla lily. Photo by Shelagh Fritz.

thriving in the gardens. The callas, growing from a rhizome, are able to grow with the rains and then store energy for next year’s growth. The arrow shaped leaves will even funnel water to the roots. As we don’t water our callas, they do go dormant, the green leaves fading to yellow.


Growing a garden with just native plants is a wonderful goal, but gardeners can also select suitable plants for their area that are not native. Taking a walk around Alcatraz this month really shows how dramatic creating garden on a bare rock with non-natives can be.

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Worm Farming on Alcatraz

As part of our commitment to being as sustainable as possible, we have a worm bin on the island. One of my volunteers, Dick Miner, started it two years ago and has since become nicknamed the Worm Man of Alcatraz.

Dick outlines in a few easy steps how you can make your own worm bin.

To start a worm farm one needs a simple container. We use a Tupperware container in which small holes have been drilled for air exchange. Fill the bottom half with bedding, we use coconut coir, this is the fibrous material of the coconut. The bedding should be moist but not wet. Coconut coir can be purchased in many good nurseries.  In Marin, it’s the nurseries the specialize  in native plants that carry coir and red wigglers.  


Sturdy container for the bin with small holes. Photo by Shelagh Fritz

Next, ordering the worms. One should start with maybe a 1/2 pound of red wigglers. The worms can be ordered through worm farming websites, Uncle Jim’s Worm Farm which is in Pennsylvania is where we ordered ours from.  Another web site that is good is Worm’s Wrangler in the Northwest.  

The worms will eat most kitchen scraps, just not meat or dairy products.  They love coffee grounds, melons, and salad greens. They are picky eaters when it comes to onions, garlic, or peppers. The worms on Alcatraz are fed once a week. Dick buries the veggies in one corner of the box; and next week the next corner and so on. The worms will migrate to wherever the food is. It is vital not to let the box dry out or they will try to leave, making a very slow getaway.


Food scraps (dinner for the worms). Photo by Shelagh Fritz

The bedding should be changed when the box gets too wet.  Harvesting castings is a bit tedious.  Dick dumps out the bedding on a tarp and separates the worms from the coir one at a time.  The worms then go into new bedding.  The castings are used in our compost tea, which is sprayed on our roses.

Worm Poop. Photo by Shelagh Fritz


The worm bin stays in the greenhouse under a bench and does not get too hot, the worms can stay outside but they do need to be brought inside for chilly winter evenings.

Visitors on the free docent tour are shown into the greenhouse and get a chance to see the worm bin and if they are lucky, will have Dick as their guide.


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