Archive for the ‘Landscape-Horticulture’ Category

Life on the Hacienda: Oakland Zoo Teens Get Gardening

by | March 3rd, 2014

In case you hadn’t heard, the Oakland Zoo Teen Wild Guides (or Twigs as we call them) recently participated in a new community program here in Oakland. Trained primarily as weekend interpreters in the Children’s Zoo, this dedicated group of local teen volunteers can also be seen at the tiger, chimp and sun bear exhibits, where they answer questions and provide information about the animals. In their first long-term partnership effort, the TWGs gathered at Hacienda Peralta Historical Park in December to volunteer their services in the park’s native plants garden. This newly-established 6-acre park, located in the Fruitvale District along the banks of Peralta Creek, is one of the most significant historical sites in the East Bay, being one of the earliest European settlements in the area.
On December 8, during one of four national community service days of the year, the TWGs brought their tools, gloves, and tarps to the park for a morning of pulling invasive weeds. During several scheduled days in the spring and summer, the TWGs will be returning to Hacienda Peralta to continue their work, allowing them to witness the development of the garden over time. This program represents a hopeful new direction for the Zoo, involving the TWGs with community institutions that work to promote wildlife conservation.
But this doesn’t end with the tossing out of a bunch of weeds. As it turns out, a great deal of this invasive plant material is edible. So the TWGs transport it back to the Zoo where (after being identified and approved by the staff horticulturists) is fed out to a wide variety of herbivorous animals. (Our giraffes especially like the thorny blackberry vines.) It’s a definite win-win situation.
The other day I had the pleasure of interviewing one of the TWGs who had participated in the gardening at Hacienda Peralta in December. As a 1st year TWG, Tano was proud to be a part of the project: “It was really cool to do habitat restoration. It was fun, with lots of wildlife, but the (blackberry) thorns hurt you.” Tano told me he was excited to have discovered a new type of plant at the park that he hadn’t seen before. “It was wrapped around another plant and appeared to be stealing nutrients from it.” As a passionate devotee of science, Tano impressed me by saying that the person he’d most like to be was Charles Darwin. He even recited one of the famous scientist’s quotes about evolution.
It was gratifying to witness this young man’s passion for science and discovery. It made me realize how important these science education programs are for channeling the energies of today’s youth. As a member of the Oakland Zoo TWGs, Tano definitely seems to be heading in the right direction. So the next time you visit the Zoo, take a moment to say “Hi” to some of the TWGs. You just might be chatting with the next Charles Darwin!



The Magical World of Composting

by | September 10th, 2010

Here’s something to ponder when you’re sitting there, stuck in traffic. What does the Zoo do with all that animal poop? Do we bury it or ship it overseas? Or do we simply flush it? Hey, there isn’t a toilet big enough for that job! The answer? We make soil out if it! The Oakland Zoo’s on-site composting program, which has been underway for several years now, successfully diverts tons of waste from landfills and provides us with a valuable new resource: organic compost!

The Raw Material

It’s a big job, but here’s how we do it: Manure from elephants, giraffes, zebras and other herbivores, along with straw (soiled animal bedding) is collected daily around the Zoo. Included with this are scraps of fruit and vegetables, eggshells and other items discarded from the animal kitchens. It takes several truck loads.

Inside the Scrapper

Everything would be much simpler if it wasn’t for the straw. It makes up a huge percentage of our compostable material—somewhere in the neighborhood of ninety percent! Early on, this was causing us problems, as we discovered that straw is much slower to decompose than manure. So the Scrapper was brought in to the rescue. The Scrapper is a six-foot long bin with rotating blades that chew up the straw into smaller, more easily digestible bits—sort of like the way your teeth help out your stomach by breaking down the food in your mouth before you swallow it.

The Ag-Bag Machine

Once this is done, the material is ready to be sent to the composting machine. Visualize a giant mechanical sausage-stuffer and you’ll get the idea. Using a small Bobcat tractor, we dump this chopped material into the hopper of the machine (also known as the Ag-Bag.)  Here, it’s mixed with a special liquid to accelerate the breakdown process. Then, a hydraulic compression ram stuffs the mixture into a tube-like plastic bag (imagine a long trash bag open at both ends.) The Ag-Bag machine has wheels which allow it to be pulled slowly along the ground by the Bobcat, as it leaves the filled portion of the bag behind it, like a tail. A plastic hose is attached to the far end of the bag through which air is pumped, providing circulation. Later, the bag is fitted with a series of small vents to release the waste gases that are produced.

Bags Soaking up the Sun

For several weeks, this bag continues to be filled until it reaches a length of about 75 feet. Then, the end is sealed and a new bag is started alongside. These long gray bags sit in the sun, allowing the mixture inside to heat up. When it gets to a temperature of 130-150 degrees Fahrenheit, pathogens are destroyed. During the following months, the material breaks down, gradually becoming less like straw and manure, and more like soil. It’s basically the same process that has created topsoil for the earth for millions of years! After three or four months, the bags are opened.

The finished product is an incredibly rich, 100% organic compound that amends the soil and allows our horticulture department to grow healthy and beautiful plants throughout the zoo grounds.

But don’t think that you have to be a zoo in order to participate in the composting process. Anyone can start their own compost pile right at home. It’s very simple. Just alternate layers of waste produce with dried leaves, cover it up and let the worms do the rest. In fact, I’ve been doing that very thing for years now, using this compost to enrich the vegetable garden in my backyard. It’s good to know that nothing goes to waste—it’s all part of the ongoing cycle of life!

Are You Savanna Savvy?

by | August 16th, 2010

What is a savanna if not a place inhabited by savanna plants and animals?  Well at the Oakland Zoo, we have such a place.

Our African Savanna garden is situated near the Lion, Elephant and Meerkat exhibits and contains within it a nice selection of native savanna plants.
We recently renovated the garden by topdressing it with several dump-truck loads of our very own compost, fixing the irrigation and adding to the existing plants (Acacia spp., Melianthus major, Sparmannia africana, Kniphofia, Aloe spp., and grasses) several Lion’s tail (Leonotis leonurus), and more grasses and aloes, including the strikingly beautiful Aloe polyphylla.  When adding the new plants, I worked with landscape architect Roseann Dal Bello on the design before getting approval from our director Dr. Parrott.  I would be remiss not to acknowledge here, for their generosity, John Miller (who donated the aloes)  and John Greenlee (who donated the grasses).

Though the ornamental plants in the garden are exotic and unusual, the weeds are fairly mundane (although the Bermuda grass IS native to South Africa, coincidentally enough).  The two most pernicious weeds here are… Bermuda grass (Cynodon dactylon) and Himalayan blackberry (Rubus procerus).  The most effective way to deal with the Bermuda grass is to spray it with herbicide, as it is nearly impossible to remove all the resprouting rhizomes from the soil (Note: because of the foliar mechanism of uptake, when applying the herbicide you will want the Bermuda grass to be in it’s most active growth – summer, full water, otherwise undisturbed, and you WILL need to apply it several times).  For the blackberry, vigilance and a Hori hori (Japanese gardening tool) to dig up the roots seem to be the most efficacious course of action, though it is a long course.  Less fearsome weeds including Bristly ox tongue (Picris echioides) and Dove’s-foot Crane’s-bill (Geranium molle) also appear, and can be sprayed or easily plucked.  In addition to the regular weeding of the garden,  I have on my maintenance schedule to prune the trees and shrubs and cut the grasses to the ground in late winter.

Another duty of mine as a horticulturalist is the adjustment of irrigation systems, and this has been tested in the savanna- I had to replace a broken head, fix a cracked lateral, monitor the unreliable valve, and because of the garden’s unusual shape (curved triangle) it being difficult to achieve head to head coverage without any over spray; with a very slim margin of wiggle room on the arc of each head, I have found it necessary to adjust the rotor heads periodically as they slip/slide and begin to spray into the path.

Our future plans include adding Arctotis, Ixia and Watsonia to the garden, and we will at the Member’s Nite event be exchanging four-inch pots of the amazing Juncus effusus ‘Afro’ rush for the nominal contribution of $5 to raise money to this cause.  I hope to see you there!

Thanks for reading, I gladly welcome any questions or comments.
-Landscape-Horticulturalist Devon Curry-Leech

"South African Savanna" themed garden