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Category Archives: Plants
What is phenology? Phenology is the study of seasonal or periodic biological events such as plant leaf-out and flowering, insect emergence, and animal migration. Put simply, phenology is the science of the seasons. In order to assess the effects of climate change on California’s extraordinary biodiversity and natural resources, the California Phenology Project was established in 2010 as a 3 year pilot project. The pilot project is focusing on 7 parks, including the Golden Gate National Recreation Area.
Corny Foster, a garden volunteer, also volunteers with stewardship of Crissy Field, an area just east of the Golden Gate Bridge. A few plants in her area are being monitored as part of the California Phenology Project, and so she thought ‘why aren’t we doing this on Alcatraz’? Alcatraz has 2 of the 5 native plants that are being monitored in the Golden Gate National Recreation Area – California poppy, Eschscholzia californica and coyote bush, Baccharis pilularis. Project wide, over 60 plant species are being monitored. The species were selected based on their ability to address key scientific questions and to inform natural resource management, as well as their ability to engage the public (charisma and easy identification are important!).
Our plants are being monitored for breaking leaf buds, young leaves, flowers, open flowers, pollen release, fruits, ripe fruit and recent fruit drop. Our phenology trail takes about 30 minutes to complete and we are hoping to build a volunteer group to do the twice weekly monitoring. Eventually, we hope to invite school groups out to observe the plants and to build on their school lessons, and to show them that looking closely at plants is FUN!
The island’s environment provides a unique opportunity to study the plants. We will be able to compare our flowering times with plants on the mainland and find out just how much being surrounded by water affects our plants. Plus, Alcatraz does not have any gophers, so our California poppies are never tampered with. The selected plants to be monitored on Alcatraz do not receive irrigation.
Simple to observe and record, phenology offers a way for “citizen scientists” to
learn about the rhythms and natural processes of their local environment while observing directly the important links between the living world and the climate system. If you would like to volunteer to monitor our plants, send an email to firstname.lastname@example.org.
As the seabird nesting season is about to get underway, beginning February 1st, there are a few landscape areas that we do one final weeding and tending to the plants, as the gardeners won’t be allowed back in these areas until September.
One area the volunteers weeded last week was a section of survivor plants on the west side of the island. The survivor plants include Agave americana, Pelargonium ‘Alphonse Ricard’, Chasmanthe floribunda, and Aloe arborescens. All of these plants are quite happy on their own but a little weeding never hurts!
The aloe, commonly referred to tree aloe, candelabra plant or Krantz aloe, is a plant that we have been giving some extra attention the past few years. The bush aloe was once a full stand, approximately 20 feet across. But, the weight of all its beauty caused the aloe to collapse in 2006. We had repotted some of the smaller plants and grew them in the greenhouse, transplanting them back when they filled a one-gallon pot.
While we cleared away oxalis and weedy mallow, the original aloe ‘trunk’ could be seen. The trunk had fallen over and was sprouting new plants, just like a nurse log in a forest. A nurse log is very common in woodlands, where an older tree has fallen and as it begins to decompose, seedlings take root.
With the aloe listed in Pam Peirce’s ‘Wildly Successful Plants’, this must be a tough plant, especially to survive on Alcatraz. Native to the Eastern Cape Province of South Africa, the aloe was used as plantings on top of earth embankments, creating corrals for livestock. The plant travelled to Europe in the early 1700s with explorers and later arrived in California with the early Spanish settlers. How the plant arrived on Alcatraz is a mystery, but it certainly is a good plant choice. The aloe is thriving in poor, well-drained soil, receives full sun and tolerates the cool coastal summers. The plant also happens to be deer resistant (not that we have that problem), but we do protect it against seagulls!
A few of the propagated plants were established along the road that takes visitors through the Prisoner Gardens. We also have a yellow blooming aloe, donated from the Ruth Bancroft Garden that is blooming right now. All of the aloes are great for attracting and feeding hummingbirds.
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
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.
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’.
Of all the plants on the island, the ones that get the most attention are the agaves. Agave americana covers the southern slope of the island and greets visitors as they approach the island on the ferry. Originally planted by the military in the 1920s, these natives to the southwest and Mexico are excellent in coastal conditions and stabilizing slopes. They also have a sharp needle at the tip of each leaf that perhaps was useful in keeping inmates out of areas.
With the common name of the century plant, Freddie Reichel, the first secretary to the Warden in 1934, called the agaves the ‘inaccurate timekeepers’. The basal rosette of leaves takes between 10 and 15 years to send up a flower; but for impatient gardeners, it would seem like a century.
The flower spike is quite dramatic, and often visitors mistake it for a tree. The spike can rise up to 26 feet in height (8 meters). Once the plant has flowered, it will then die; but in the meantime, the plant has sent out new adventitious shoots (pups), that will take the place of the parent plant.
While this is not the plant that tequila comes from, the plant does have many other uses. The fibers in the leaves were used by natives to make rope, sew, or to make rough cloth. The seed pods are edible and a sweet liquid can be harvested from the flower stalks before the flowers open.
This past summer, the stand of agaves by the Warden’s house had one plant that was ready to flower. Being a gardener on the island certainly has its perks, and I was able to watch the flower spike reach for the sky and take a photo every week to see how fast it would grow. I first noticed the spike rising above the leaves mid-May and finished reaching the full height with the seed pods expanded mid-September.
The flower spike has now taken its place alongside the other centuries. Now that the flowering is finished, I can start watching the new pups grow.
Autumn in North America is automatically associated with vibrant leaf color. Autumn in the Bay Area may not be as dramatic as on the East Coast, but the plants here are also anticipating the changing of the season.
Aside from an unusual sprinkle of rain in July, our landscape has only received fog drip since the last significant rainfall in May. Needless to say, the plants on Alcatraz that do not receive additional irrigation can hardly wait for the first rainfall.
Succulents are well suited to our Mediterranean- like climate; they are just now beginning to show signs of dryness. Many of the signs are actually adaptations to the lack of water. All of the succulents are able to store water in their highly evolved stems, leaves, and/or roots. In fact, when water becomes scarce, some succulents will shed their lower leaves to conserve water. As soon as water becomes available again, the plant begins to store water again in the existing leaves and will grow new leaves as well.
Another response is a change in leaf color. Chlorophyll is responsible for the green that we see in plants; but there are other pigments in plants that give red, blue, orange and yellow colors. It is thought that in response to stress, plants will show pigments that would otherwise be hidden. Anthocyanin and betalain are pigments that give a red hue.
Several succulents on Alcatraz are
now showing their true colors. Crassula ovata, the common Jade plant, normally has a leaf edge ringed in red, but now has the entire leaf deepened in a shade of red and while the red edge is very brilliant.
Aeonium arboreum normally displays a rosette of green leaves; but now each leaf is edged in red, plus the lower leaves have been dropped to conserve moisture. Another succulent, Aeonium cuneatum has also adds to the display of color. This succulent normally is grayish green but has taken on more rosy gray leaves.
Regardless of the cause, the gardener can appreciate the changing seasons and design with the red hues in mind.
Abandoned and overgrown orchards are pretty common to see in the country side, left for the birds and wildlife to enjoy the harvest. Of all the survivor plants on Alcatraz, perhaps some of the most unexpected are the apple trees. Not exactly an orchard, the two trees were planted years ago in the Prisoner Gardens on the west side of the island and they are still producing bright red gems with a yellow blush every autumn.
The trees are believed to have been started by an inmate gardener, who likely had apples for a snack and saved the seeds to grow. I’m sure any gardener today has thought about saving their apple seeds and starting their own trees; but few have the patience to wait years for the tree to mature, not to mention having a safe place where the seedling can be nurtured.
However, Alcatraz inmate gardeners had that time.
Twig cuttings of the trees were taken last December and were couriered to the National Plant Germplasm Repository for Apples, a department of the United States Department of Agriculture for Plant Genetic Research in Cornell, New York, with the hopes of identifying the apples with a cultivar name.
So far, researchers at the Repository have not been able to find a correct id for the trees. As the Alcatraz trees lack a graft union, where the scion (the top half of the tree) is joined to the trunk (the rootstock), we can reason that the trees were started from seed. Starting plants from seed increases the genetic variation and the difficulty of positively identifying the trees. If the trees had been started from vegetative cuttings, then the genetics would be the exact same as the parent plant and would most likely be from a known apple tree which would already be in the database.
While we do not have a name, we can still preserve the trees by keeping them growing. Keith Park, Horticulturist for the National Park Service at the John Muir House in Martinez, California was consulted. Park is the caretaker of Muir’s fruit trees and has also worked as the horticulturist at the well- known Filoli Gardens in Woodside, California and looked after their heirloom fruit trees.
Dormant twig cuttings of the Alcatraz apples were taken during the winter and Park grafted them onto a suitable rootstock. Park chose the rootstock MM.111 EMLA. Rootstocks are used to give the mature tree qualities the desired tree lacks, mostly to control the tree height and to give disease resistance. The scion still determines the kind of fruit produced. What does the MM.111 EMLA stand for? Much of the initial apple research began in England in the early 1900s. The ‘M’ refers to the East Malling Research Station in England; the ‘MM’ prefix refers to Malling-Merton when hybrid trees of the Malling series were crossed with ‘Northern Spy’ apples in Merton, England in the 1920s. The ‘EMLA’ suffix stands for ‘East Malling /Long Ashton’ when rootstocks were bred to be virus free in the 1960s. (Click here to read more about rootstocks).
The MM.111 EMLA rootstock is recommended for dry sandy soils in low rainfall areas (perfect for Alcatraz), has good anchoring capacity, rarely produces root suckers and has good resistance to woolly apple aphids.
Park had rootstock that was already a few years old, and so the diameter of the rootstock was slightly larger than the scion. Typically same size diameters would be used, but for us, it would work. Park described his handiwork:
“When I have scion and rootstock material of different sizes I usually do a cleft graft, which involves splitting the rootstock down the middle with a knife about 3/4 of an inch, then shaving the bottom end of the scion to a long, even wedge (like a flat-blade screwdriver) and inserting it into the cleft in the rootstock. The most critical part is aligning the cambium of each piece. If the pieces are not exactly the same diameter (as is often the case) then I insert the scion to one side of the cleft and match up the cambium on one just one side.”
“The next step is to seal and secure the scion to its rootstock so it doesn’t dry out or fall out. I discovered a product called Parafilm, which is a wax impregnated cellophane tape that works great.”
“After the graft has taken the only real maintenance is to periodically rub off any adventitious growth from the rootstock. I’ve heard you should also prune off any flower buds if they appear on newly grafted trees, since it just consumes plant energy at a time when you don’t want fruit anyway.”
The grafted apple trees were grown outside in Woodside and we now have a few of the new apple trees back on the island. One of the trees, planted in the Electric Shop, barely lasted a week, as the wind snapped the tree in half. Luckily, we had a replacement and we can reuse the rootstock. Gardening on the Rock is a challenge but one with many rewards.
Meeting people that are passionate about their work is always exciting. Not only do you learn something new but it is hard to walk away and not feel inspired to delve into your own specialty of some sort. On Thursday, we were treated to a visit from John Greenlee and Neil Diboll. John is the grass guru from Greenlea & Associates and specializes in grass ecology and designs meadows for private residences, as well as notable sites such as the San Diego Zoo and Disney’s Animal Kingdom in Florida. He’s also author of The American Meadow Garden, a fantastic guide to creating natural alternatives to the traditional lawn. John’s passion for his work was evident as soon as we showed him our neglected historic lawn.
Not many people can look at a dead patch of grass less than 1500 square feet in size for half an hour and talk about the many possibilities for it. In fact, not many people would see a possibility at all. During the penitentiary days, the west lawn was kept watered, manicured and was green all year. Actually, an inmate gardener was warned about using too much water for the lawn. The lawn, made up of non-native annual grasses, is lush and green during the winter and spring but then quickly turns into brown grass showing dusty bare ground during the summer months. This dead lawn serves as the backdrop to our now restored borders along the west road. No matter how beautiful the borders look, the eye can’t help but be drawn to the huge eyesore of the former lawn.
John has some interesting facts about lawns in the United States:
-Lawns are the fourth largest ‘crop’ in the States. Corn, soybeans and wheat are the first three crops.
-30% of water on the East Coast is used to water lawns; compared to a staggering 60% of water used to care for lawns on the west coast.
Obviously, lawns in dry California do not make sense. Neil coined a new term to describe this phenomenon: dis-ecological. Re-creating a lawn on an island without any fresh water would certainly be ‘dis-ecological’.
John described how using four or five types of native grasses could be used to create a meadow. Naming a few – Stipa pulchra, Elymus trachycaulis, Muhlenbergia species and Carex pansa, he explained that “grasses are framework that everything else hangs on”. Another component of planting a meadow would be to plant bulbs as “flowers are there for the sizzle”. South African bulbs, as well as native California bulbs would do well in our Mediterranean climate. Tritonia, Fritillaria, Tritelia, Dichelostemma capitatum (blue dicks), and Calochortus nuttallii (Sego lily) would be perfect.
John also gave us pointers for turning a plan on paper into an actual meadow. The first step would be to try to reduce the seed bank in the soil. Forty years of weed seeds have accumulated since this lawn was last cared for and those annual seeds is what have been providing the ‘green lawn’. Other than using roundup, John suggested watering the ground now to germinate as many of the seeds as possible. The germinated weed seeds can then be killed off using an acetic acid solution (vinegar). He advised against tilling the soil or amending it, as this would only bring more weed seeds to the surface. Plants need to survive in the existing soil, or they will never be happy. John described that plants should be thanking you for giving them dry, sandy, nutrient deficient soil. John commented that we only have annual grasses to contend with, so we are one step ahead already. Planting by plugs would speed up the establishment of the meadow by a full year, instead of taking two years with grass seed. We could potentially see a beautiful meadow this time next year! Once the plugs are in, the area would need to be kept weeded and watered until established. John explains as a general guideline “design what we can afford to water”; with our rainwater catchment sitting right next to this lawn, we will have sufficient water. Mulching around the plugs will help to prevent further germination of weed seeds and Neil recommended using corn gluten as an organic pre-emergent.
Once established, the meadow would have very little maintenance with cutting once a year. John said the goal of a meadow is “it has to say it’s a meadow; not ‘when are they going to mow that lawn’”.
After John and Neil left, the volunteers and I talked excitedly about our meadow-to-be; and actually, we were still talking about it this morning too. Seeing the possibilities through the neglect is a real skill; a skill that John, Neil, the Garden Conservancy team all share.
As we settle into our summer garden maintenance routine, there are a few garden tasks that we do weekly. This time of year we are kept busy watering plants and deadheading the spent flowers. Many first-time volunteers are unfamiliar with the term ‘deadheading’ and I have the opportunity to show them something new.
So, what exactly is deadheading? Simply, it is the removal of dead flowers. By removing the dead flowers, the plant is tricked into producing more flowers; all the plant really wants to do is produce seeds to ensure the next generation of its kind. When we remove the flowers right before the plant begins to put energy into producing seeds, the plant instead puts energy into making more flowers for us to enjoy all summer long. As well, removing dead flowers keeps the plant looking tidier.
Deadheading does take a certain type of person though. As you can imagine, removing tiny flowers one-by-one from 4.5 acres of gardens is time consuming and having patience, an eye for details, and a strong back helps.
Most plants are deadheaded in the same basic way – cutting the flower back to the next live leaf is a good general rule. However, for pelargoniums, they do look better when done a certain way. For these plants, the entire flower plus the flower stalk must be removed. If only the flower is removed, the stalk will eventually die-back leaving an unsightly stick. And while it may only be one stick, over an entire section of planting of pelargoniums, these little ‘sticks’ will prominently catch a person’s eye. Removing the flower and stalk is easy enough – simply firmly hold the base of the stalk in one hand and then bend down the flower stalk. Pelargoniums also tend to have yellowing leaves underneath that will shrivel and fall to the ground. A good practice to help prevent disease and buildup of insects is to regularly clean these leaves up and compost them.
Other island plants that benefit from deadheading are Osteospermum, Arctotis, Penstemon, snapdragons, rose, Zinnia, Limonium, Calendula, Centranthus.
This past Monday marked the 50th anniversary of the famous escape of the Anglin brothers and Frank Morris, as portrayed by Clint Eastwood in the movie Escape from Alcatraz. Cleverly arranging to be in cells next to each other, four men planned the elaborate escape. Back in 1962, seating at meal times was arranged by cell location – meaning that the foursome sat at their own table and had every meal to plan and update each other on their progress. Planning likely took a year and a half before beginning a six month dig out through the back concrete wall surrounding the air vents of their cells. Their route would take them up to the roof through the utility corridor. Unfortunately, all that planning could not have predicted that when Allen West dug through the back of his cell, he encountered a pipe that would let him go no further. The three remaining inmates fled to the water where they used homemade rafts to brave the frigid waters of San Francisco Bay.
Family of the Anglin brothers was on the island along with many members of the media to speculate if the trio made it or not. With the three still officially wanted by the FBI, the search continues.
There are a number of other escapees; however they get much less press coverage – the plants.
After the closure of the prison in 1963, the gardens were abandoned, leaving the plants on their own to either perish without the constant care of gardeners; or to thrive. These garden escapees chose to thrive and are well suited to dry windy summers, poor rocky soil and near constant wind. If a plant can cope with these conditions, it almost deserves its freedom by growing where it pleases.
High on the wanted list (or unwanted list as the case may be) are the usual suspects – ivy, blackberry, and honey suckle. A few other plants are more recognized as ‘garden plants’ – calla lily, Chasmanthe floribunda, sweet pea and Acanthus mollis. Nasturtiums try to sneak into most garden areas – sending their long tendrils cautiously at first, and then before you know it, the vine is 10 feet long and clambering over its neighbors. The most dramatic escape, almost comparable to the Great Escape of 1962, is Elliot Michener’s fig tree. In the forty years of the gardens being neglected, the fig was happy to spread out and take over a portion of the west lawn. This escape has a happy ending, as now the overgrown vegetation provides habitat for snowy egrets, which are back on the island, right now in fact, raising their chicks amongst the ripening figs.
The escapees give a glimpse of what introduced plants will do on an abandoned plot of land, and what other creatures will find opportunity with a new habitat created.
I’ve written a few times about
the Cellhouse Slope that faces San Francisco – the hours spent weeding oxalis in the rain and wind on the steep slope; but I can’t resist writing about it again.
I am very pleased to report that the Slope, as all the gardeners call it, is looking fantastic this year! The bright pink is easily visible from the city, even as far as Fort Point, the military fort on the south end of the Golden Gate Bridge! Amazing enough, but there’s more – this is the first year since we started rehabilitating this area that we never had to weed oxalis on the section of the slope that was begun in 2007! Both of these achievements are something that all the volunteers and garden staff are very proud of.
We got ambitious and decided to go beyond our original plan and restore the entire slope to its original planting plan of having the ENTIRE slope planted with the ice plant, as is recommended in the Cultural Landscape Report. We began snipping cuttings last summer and grew the plugs in 4” pots in our greenhouse. We were able to weed the slope of germinating grasses, wild radish and mallow weeds and were able to stay ahead of the lush growth that came with the rains this past fall and winter. We weeded and planted simultaneously, clearing an area and then planting it right away. We have now covered the second half of the slope, and the new plants have even started to flower. I guarantee that next May, this slope will be truly incredible (and I may just have to write about it again).