Category Archives: Plants

Spring Already?

The sky around the San Francisco Bay Area has been very active this week – from storm clouds to Fleet Week’s Blue Angels practice runs. Dramatic clouds and sudden rainfalls, while unexpected for this time of year, were

Storm clouds approaching over the Golden Gate Bridge with sunshine and a rainbow over Sausalito. Photo by Shelagh Fritz

refreshing and washed the island clean after the end of bird nesting season. The plants soaked up this first substantial rainfall and were sparked back to life after the dry summer.

Surprisingly, spring bulbs have been emerging in Officers’ Row. Daffodil leaf tips are poking through the soil and grape hyacinth (Muscari  armeniacum) have shot up over the last couple of days. Other bulbs such as Chasmanthe and Watsonia have been nudged into growing and their bright green leaves are a refreshing sight. Bear’s breech (Acanthus mollis) leaves are unfolding as well, each leaf being an exquisite living art unfurling from a knarled exposed root.

Acanthus mollis leaves emerging in the Prisoner Gardens. Photo by Shelagh Fritz


Daffodil leaf tips in Officers' Row. Photo by Shelagh Fritz












All of these plants have origins in other mediterranean climates similar to that of the Bay Area. They are adapted to dry summers; being baked in well drain soils and with the slightest moisture can be triggered into growing. Examining the survivor plant list for the island, it is no surprise that many on the list are from climates similar to ours.

Elsewhere on the island, the nasturtiums (Tropaeolum majus) continue to self-sow where

The next generation of nasturtiums beginning. Photo by Shelagh Fritz

they please. The nasturtiums were introduced to the island in 1924 by the California Wildflower and Spring Blossom Society as part of a beautification effort by the military. Whether you consider them invasive or successful, they are a part of the island’s rich horticultural history. Seeing them sprout now is reassuring that another generation will continue to decorate the slopes with brilliant orange and yellow flowers.


While some visitors plan their vacations to not be in rain, a visit to the island during a storm is exciting and the island feels more alive with the elements. Watching a storm approach through the Golden Gate and sweep toward you is a vacation memory that you cannot put in a photo album.

Sunrise this morning over Alcatraz. Photo by Shelagh Fritz

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Finding Beauty

Garden staff and volunteers have been busy this week cutting back plants that have entered their dormancy period. This time of year is much like the autumn for elsewhere in the country, except for crisp frosts that kill plants, our dormancy is brought on by our dry season. Many of our plants are from other Mediterranean climates and have adapted well to cope with our climate.


Still, it is easy to find beauty amongst the seemingly dead and dry plants. The seed heads left behind are sometimes more interesting to look at than the flowers.


One of the most common plant id questions I hear is ‘What are those trees by the Warden’s House?’ Resembling trees with their height, the Dr. Seuss looking trees are actually the flower spike of Agave americana.  Silhouetted against the skyline of the city or the evening light, the spikes are so dramatic that even non-plant people wonder what they are. Commonly called the century plant for how long it takes to flower, the plant sends up one spike of flowers after 8 to 10 years; the plant puts all of its energy into sending up the flower spike that it actually dies. The next generation of plants have already begun at the base of the flowering succulent to repeat the show in a decade.


Agave americana with San Francisco. Photo by Shelagh Fritz


Agave americana under a full moon. Photo by Shelagh Fritz













Aeonium arboreum planted en mass are another

Aeonium flower spikes. Photo by Shelagh Fritz

succulent that provides a show with their flower stalk. The succulents planted long ago under the water tower all bloomed at once this year. Located in a closed area that is enjoyed by visitors on the garden tour, the view is impressive.


The west side inmate gardens are a host to surviving plants from the penitentiary. With the cell house as a backdrop, Acanthus mollis, bear’s breeches, 4 to 5 foot flowers standing tall above its once glossy green leaves. The leaves are fading and we will be leaving the flower stalks to provide interest for another month.


Acanthus mollis flower spikes. Photo by Shelagh Fritz

Many perennials in Officers’ Row are putting on a display of their own. Gaillardia, Agapanthus, Crocosmia, Foxgloves, Hebe and Artichokes are signifying the end of their growing season by setting seed. Many of these plants can be deadheaded to encourage the plant to keep blooming. The ‘deadheads’, as we call them, can make a curious dried bouquet. One of the best dried flowers on the island is Limonium perezii, sea lavender or statice, which holds the purple color well.


Elsewhere on the island, Shirley poppies and Crocosmia both have tiny seed pods that are appealing.


From the tall succulents to the more average size perennials, leaving flower stalks stand allows gardeners to enjoy their hard work longer into the year. Just like the gardens soften the harsh island, finding the surprising beauty in dead flowers will hopefully inspire people to appreciate all that surrounds them.

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Gardening by Trial and Error

Much of gardening is learned through experience – by working in the soil, getting your hands dirty and being open to make changes.

The inmate gardens on the west side had much to teach us about gardening on the Rock. Restoration of these gardens started in the fall of 2008 and by the spring of 2009, the overgrowth had been cleared, pathways rebuilt and new gravel added. The beds were amended and new plants were chosen. Plants were selected to give the look of the 1940s-1960s gardens that the prisoners created and tended. The original gardens resembled English cottage gardens and so we worked at finding plants that would fit, but that would also be drought tolerant.

The inmate gardens in early summer. Photo by Shelagh Fritz

Plants such as Armeria maritima, Coreopsis, Dianthus, Oenethera, Cosmos, Gaillardia, Scabiosa, Linaria and Huechera sanguinea were some of the plants that we tried. The gardens looked gorgeous in the spring but by mid-summer, the unrelenting wind of the Pacific was taking a toll. Even the rainwater catchment that was installed was not enough to help all the plants through the dry summer.

We took this lesson to heart and looked for plants that could provide the historic look, be drought and wind tolerant and look really good well into October. A tall order, but not impossible.

Salvias seemed a likely candidate. While not known to have been on the island previously, they were likely to do well on the island and still give a cottage style look. This past January, we planted several different species of salvias and they are all doing well. Salvia clevelandii filled

Salvia clevelandii. Photo by Shelagh Fritz

an exposed corner of the garden. The very fragrant leaves and blossoms held on until this past week, when they were cut back to encourage new growth. Salvia leucantha, Mexican bush sage, is very common in San Francisco and it has done well on the island too. Salvia nemorosa ‘East Friesdland’ has done well at the front of the border and has bloomed twice this year with cutting off dead blossoms. Salvia chiapensis, Chiapas Sage, while from the cloud forests of Chiapas, Mexico has done surprisingly well under the fig tree in the shade. Salvia microphylla hybrid is continuing to bloom and has not needed any pruning at all; autumn is actually its peak bloom time. And lastly, we also chose Salvia ‘Waverly’ for the constant pale white blooms.

Salvia chiapensis. Photo by Shelagh Fritz


We also planted low growing evergreen perennials and shrubs at the front of walkways and tucked in annuals behind, to hide the annuals as they died back. We propagated a surviving white hebe to hide the calla lilies during the summer; and planted dwarf agapanthus and heliotrope to cover columbine, foxgloves and homeria leaves when they passed their prime.

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In Bloom: Dahlias

Some plants never go out of style and Dahlias have earned their space in gardens over the past two centuries. Dahlias were popular on Alcatraz during the 1940s and 1950s and are easily identified in photographs of Officers’ Row. Mrs. Casey, the medical officer’s wife, tended to her dahlias when she was not busy in her home.

The Medical Officer and his wife, Mrs. Casey, with their dahlias outside of their Officers' Row home. Photo courtesy of J. Babyak, 1961ca

Last year, dahlias were re-planted in Officers’ Row and this year’s display is even better. Heirloom varieties were chosen to give the ‘look and the feel’ of the historic photos with lots of red, orange and yellow blooms. Seven varieties of old-fashioned tubers were chosen that would had been available to the gardeners of Alcatraz:

‘Andries Orange’ (1936), ‘Clair de Lune’ (1946), ‘Old Gold’ (1947), ‘Kaiser Wilhelm’ (1881), ‘Thomas A. Edison’ (1929), ‘White Aster’ (1879), and ‘Yellow Gem’ (1914).

Dahlia 'Old Gold'. Photo by Shelagh Fritz

Dahlia 'Kaiser Wilhelm'. Photo by Shelagh Fritz


Dahlias are fairly easy to care for; they prefer soil rich in full sun, organic matter, and regular water. The Officers’ Row gardens are protected from the harsh Pacific winds on the east side of the island and enjoy a full eight hours of sun during the summer. The organic matter is supplied by our own compost with supplements of sheep manure in the spring. The water is provided by a rainwater catchment from the restroom roof by the Warden’s House. The rain barrel captures 500 gallons and supplies enough water for the summer months. Last year, we began utilizing this rain catchment and so could justify the use of the water for growing dahlias again.

The average winter temperature on Alcatraz is rarely below 40?F (4.4?C) and so the tubers are left in over the winter. Regular removal of dead flowers over the summer ensures a steady bloom to the end of September, Dahlia ‘Yellow Gem’ bloomed until October.

Dahlia 'White Aster'. Photo by Shelagh Fritz

Your best opportunity to see the dahlias are on Wednesdays when Officers’ Row gardens are open for our ‘Ask the Gardener’.

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Christmas in July

The plant life on Alcatraz is mostly made up from non-native plants. Plants were brought to the island by people who were found themselves on the island by duty or by punishment. Today, these surviving plants represent gardening trends from years past. Mr. Freddie Reichel, one of the first gardeners for the penitentiary prison made connections with key horticulturists who recommended plants that would do well on the island. These plants, then considered rare and novel, are more common in the Bay Area now, but they are part of the living history on Alcatraz.

Blooming right now, one of these novelties is the New Zealand Christmas tree, Metrosideros excelsa. Two specimens were planted in the inmate’s gardens likely during the late-1930s on the west side of the island and are flourishing. Wisely chosen, these magnificent trees thrive in coastal conditions – tolerating wind and salt spray, and preferring well drained soil with moderate water.

Visitors from New Zealand this week were surprised to recognize the tree and asked if it was the Pohutukawa tree, referring to the tree by the native Maori name. In New Zealand, the tree blooms around Christmas time during the southern hemisphere summer. Seeing a familiar tree bloom in July instead of December in a different country is like chancing upon an old friend while on vacation.

New Zealand visitors pose with their native tree. Photo by Shelagh Fritz

The tree is highly regarded in native Maori culture for its strength and beauty. The Latin name Metrosideros comes from the Greek. Metra means

Metrosideros flowers. Photos by Shelagh Fritz

‘heartwood’ and sideron refers to its ‘iron’ strength. Excelsus is Greek for ‘highest’. What looks like bright crimson red flowers are actually clusters of stamens, the male reproductive part of the flower.

Both trees on the island are in excellent heath and have been shaped by the wind over the years. We have been successful at propagating from cuttings one of the trees and so we are working to conserve the genetic material of these historic trees.

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Camouflaged weeds

Plants never stop amazing me. With their power to harness energy from sun and give us oxygen as a by-product; they provide us food, clothing, and beauty. Yet a group of plants that only gets noticed when it is the wrong spot deserves a bit more respect. These would be the weeds of our gardens.

The past rainy winter and spring produced weeds continuously. The weeds are well adapted at growing quickly to complete their lifecycle and set seeds to start the next generation before 1) the dry summer begins and 2) before being noticed and be pulled by a gardener. As I worked my way through the gardens over the past couple of months, I was impressed by how smart some of the weeds were for being able to hide themselves in amongst similar leafed plants.

Epilobium growing with Fuchsia 'Grand Harfare'. Photo by Shelagh Fritz

I found fireweed, Epilobium, growing amongst Fuchsia ‘Grand Harfare’ and Jupiter’s beard, Centranthus ruber. Not until the weed had outgrown its hiding place and was flowering that it called attention to itself. The fuchsia’s leaves have an almost identical vein pattern to the epilobium and the pinky hue of the fireweed accented the coral tones of the fuchsia. The fireweed was able to disguise itself with the jupiter’s beard by being a light green that matched well, again, the leaf shape was almost indistinguishable.

Epilobium with Centranthus ruber. Photo by Shelagh Fritz







Solanum americanum, American nightshade, is a very common weed on the island. It is very easy to pull when young but once established, the stems usually break off when pulled.

Solanum growing with Coreopsis 'Nana'. Photo by Shelagh Fritz

I found a young plant growing with tickseed, Coreopsis ‘Nana’. The deep green of the leaves of both plants is very much alike. Perhaps the ‘smart’ nightshade did not


realize that it was trying to camouflage itself with a dwarf cultivar and it quickly outgrew its companion.

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New Historic Photos Come to Light


  ‘How do you decide what to plant?’ is a common question that I get asked by visitors to the island. With choosing the right plant for the right place in a cultural landscape there are a few more considerations than your average backyard.

We aim to give ‘the look and the feel’ of what the gardens would have looked like during the days of the military era (1853-1933) and during the maximum security federal prison era (1934-1963). Detective work by Carola Ashford in the early days of the project built up a collection of historic photographs that we rely heavily upon. Using these photos, along with oral history interviews and historic letters, we were able to create gardens that echo the color schemes, textures and purpose of the original gardens.

Amazingly, historic photographs that we have never seen

Kathe standing in their garden. Photo by Al and Mildred Kaepple

before are still coming to light. Kathe Poteet had her early childhood years on the island in the 1950s while her father worked as the business administrator.

Kathe recently passed along a collection of photographs her parents had taken of their home on the Rock.

The photos reveal the Parade Ground, an area that has not been restored yet, to have once been a well-tended neighborhood with roses and hydrangeas at the foundations of the homes surrounded by manicured lawns. Many of the photos show Persian carpet, Drosanthemum floribundum, spilling over the seawall and the grove of Eucalyptus by the dock is still young.

The south end of the island in the 1950s. Photo by Al and Mildred Kaepple

The south end of the island today. Photo by Shelagh Fritz


Kathe is planning on attending the Alcatraz Alumni Weekend in August when past residents visit the island to share their experiences with visitors. It is through this once-a-year occasion that we have been able to compile an extensive collection of landscape photos.

I hope to meet with Kathe to find out more about the people in the photos and about her father, who obviously had a green thumb.

Al Kaepple in front of the family home. Photo by Al and Mildred Kaepple

Looking at the photos, the pride the residents took in tending their gardens is clear; it is easy to imagine calling Alcatraz home.

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Marking the Passage of Time

Summer is slowly showing itself on the island and the change of seasons can be seen in the blooming gardens.

A section of the main road, as visitors walk from the dock to the cell house is affectionately called the ‘fern wall’, even though in summer there is no evidence of ferns anywhere. The granite blocks that form this retaining wall was built in the early military days and was softened by moss and ferns that came to the island likely as spores in the imported soil.

The fern wall in 1924. San Francisco library photo

As the winter rains cease, the native fern, Polypodium californicum turns a golden  brown and then go dormant. The fern wall undergoes a dramatic change from lush green to vivid pinks as the Jupiter’s beard, Centranthus ruber, bursts into the season. At the base of the wall is a collection of Pelargonium that are survivors from the prison days – ‘Brilliant’, ‘Mrs. Langtry’ and P. quercifolium that add to the hue of pinks.

Fern wall in the spring. Photo by Shelagh Fritz

Fern wall in the summer. Photo by Shelagh Fritz

To be accurate with historic photos of this wall, last year, we planted plugs of Persian carpet, Drosanthemum floribundum in the cracks of the granite blocks that will eventually cascade down the wall. With living walls being the current trend in gardening, this wall on Alcatraz was way ahead of its time.

The wall in the 1940s. Photo by Joseph Simpson

When the fog rolls in, the intent of the original gardeners to create cheerfulness on a barren island must have been no easy undertaking. I also cannot help but wonder if the inmate gardeners marked the passage of time with the changing blossoms.

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Cheerful face towards San Francisco

Has anyone been curious why the hillsides of Alcatraz are turning pink?

Pink drosanthemum blooming on the cellhouse slope. Photo by Shelagh Fritz

Pink iceplant, Drosanthemum floribundum or Persian carpet, has been very prominent this past week from Crissy Field, Fisherman’s Wharf and on a clear morning, even from Doyle Drive coming into the city.

The planting of the tiny succulent was part of a beautification effort undertaken by the military in 1924 after being pressured by the vocal citizens of San Francisco to landscape the barren the island. Inmates took part in the planting and soon, carpets of pink cascaded down the steep hillsides, not only stabilizing the soil but providing a cheerful look desired by San Francisco. It is somewhat ironic that a gentle soft pink was chosen to mask the harsh prison.

Historic view of the Persian Carpet from the parade ground. Photo by C. Stucker

Neglected cellhouse slope in 2007. Photo by Shelagh Fritz

With 40 years of neglect, the iceplant on the cellhouse slope suffered and was soon choked out with oxalis, wild radish and grasses. In 2007, this historic garden area was restored.



Stabilized slope newly planted with iceplant plugs, October 2007. Photo by Shelagh Fritz

The slope was stabilized with jute netting and cuttings of Drosanthemum from elsewhere on the island were established on the slope.  Coaxing the drosanthemum to take root and to keep the slope free of oxalis has been no easy task. Staff and volunteers have invested countless hours into weeding over the past four years, but seeing our efforts from across the water, well over a mile, is quite awarding.

The slope this week. Photo by Shelagh Fritz

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Alcatraz’s bearded iris are blooming

Bearded iris has been a long-time garden favorite that even found their way onto the most notorious prison island. There are five cultivars of bearded iris that are survivors from the prison days, blooming every May without fail. One survivor, Iris ‘King’s Ransom’ blooms twice a year, early spring and again in the fall. The other four cultivars are still unidentified, and we are working at finding out more about them.

Survivor bearded iris in Officers' Row. Photo by Shelagh Fritz

 My favorite iris is in bloom right now in Officers’ Row. This clump of iris was entirely covered by ivy and blackberries until 2003, when they were cleared and began to flower again. The 3’ flower stalks are heavy with lavender blooms that catch visitors by surprise with their bubble gum fragrance. Another survivor iris smells like root beer, clearly not your average modern iris.

Up close. Photo by Shelagh Fritz

The only thing better than five cultivars of bearded iris is more bearded iris! The Garden Conservancy’s first preservation project, the Ruth Bancroft Garden in Walnut Creek is a garden haven for heirloom bearded iris. Ruth Bancroft’s collection matches the time frame of the penitentiary gardens, and so Alcatraz has received divisions of her iris for the past four years. We now have just over 30 cultivars of heirloom iris in a wide range of vibrant colors and rich scents. The iris are not troubled by the dry summers, winter rains or the salt breezes and fog. Occasionally, there will be aphids on the leaves but these are easily washed away.

Ruth Bancroft Garden iris. Photo by Shelagh Fritz

The iris will be in bloom for only another two weeks, so now is the time to walk your nose around the island finding these heirloom garden beauties.

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