Author Archive

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