One of my favorite things about gardening is trying new plants. Unfortunately, through the years a number of these new plants have not worked out. They turn out to require too much water, or look ratty in the summer, or are a magnet for pests. Although I will probably always want to try new plants, it’s great to have a few that will never let me down. One of these is the South African succulent plant Portulacaria afra ‘Variegata,’ or “Elephant Food.” It requires no supplemental water once established, is long-lived, easy to propagate from cuttings, pest-free and looks good year-round (no “off season”). With purple stems and variegated foliage (cream and green but from a distance giving an impression of yellow), this low-growing cultivar provides an interesting color contrast with other plants in the garden.
Imagine my surprise on reading a recent BBC report that the plant that has provided me with so many garden solutions can also provide one of the solutions to climate change. It has to do with the versatile way in which Elephant Food carries on photosynthesis. Photosynthesis is the process by which plants make their own food using carbon dioxide, water, chlorophyll, and energy from the sun. Plants take in carbon dioxide from the air by opening microscopic pores in their leaves and stems. Most plants do this during the day but plants growing in very dry environments cannot afford to lose the water vapor that may escape from their pores in the hot sun. So, some desert plants, such as the cacti, open their pores at night to capture the carbon dioxide (so, less water loss). They then change the carbon dioxide into malic acid, which can be stored overnight and converted back to carbon dioxide for photosynthesis the next day when the sun is shining, and their pores are closed.
According to the BBC report, a very few plants—possibly only 25 species on earth—are able to switch from one method to the other according to how much moisture is in the air. One of these plants is Elephant Food. This versatility makes the plants especially efficient at taking carbon out of the atmosphere, providing a valuable “carbon sink.”
The South African government’s Working for Ecosystems program proposes to plant 2.5 million acres of the wild form of Portulacaria afra. The amount of carbon sequestered by this giant thicket could offset almost 3 times the amount of emissions produced in the U.S. in 2019. And there are other benefits. Unlike my low-growing variegated form, the wild form grows upright and can reach 16 feet, providing cooling shade. The planting and tending of the cuttings can provide jobs for local people. It can help control erosion and its leaf litter can enrich the soil. And it could provide a valuable source of food for wildlife, including elephants (which is where it gets one of its common names). Other common names include Spekboom and Miniature Jade.
The article can be found on line at www.bbc.com/future/article/20200203-the-south-african-plant-fighting-climate-change.
Categories: Local News