Did you know our indigenous Portulacaria afra, also known as Porkbush or Spekboom, has become the poster plant for climate change because of its ability to absorb more carbon dioxide from the atmosphere than most other plants?
Its credentials are confirmed by the South African National Biodiversity Institute, with a stand of Porkbush having “the ability to remove more carbon from the atmosphere than an equal amount of deciduous forest” – like, for instance, the Amazon rain forest.
“Our cities are already urban forests, so imagine how planting Porkbush as small trees, shrubs, or hedges in every garden could double the capacity of our ‘green lungs’ to clean the air,” says John Sauer of Ngena Succulents.
How to grow
Porkbush not only has carbon-sequestering properties, it is a drought-tolerant garden plant. He recommends planting in full sun, as plants grow upright and develop the red stems that make them so attractive.
In shadier gardens the growth is looser, and the stems are greyish- green. Plants grow in normal garden soil, if there is good drainage. They do well in pots too.
Using in the garden
The original P afra grows 2 metres to 5m high and requires virtually no care. It can also be grown and clipped as a hedge. More prostrate varieties are excellent groundcovers.
Their air cleaning properties make them good indoor plants in bright light, even some sunlight. Let plants in pots almost dry out before watering.
Edible and healing
The crunchy green leaves have a slightly sour taste and can be added to salads and even stews. As a traditional remedy, the leaves are chewed to quench thirst and relieve dehydration, as well as to treat sore throats.
The collection includes the following varieties:
• P afra Variegata (Rainbow bush) has yellow leaves with green mid-stripes. It grows laterally, cascading over the edge of pots, hanging baskets or raised planters. The stems are a darker red-brown.
• P afra Minima (Elephant mat) is a cascading variety, ground-hugging, to form a spreading 60cm wide mat. It has tiny dark-green leaves, strung along bright red stems like a necklace. Tuck into nooks and crannies in the garden, use as an edging for mixed containers or as a house plant on a sunny windowsill.
• P afra Limpopo has leaves almost four times normal and a sturdy, light reddish-brown stem. It is endemic to the Limpopo province. It grows upright and could be grown as a small tree or shaped into a substantial shrub.
Sauer’s favourite miniature variety, which he has yet to identify, has an upright but arching growth which produces a nicely-shaped plant. The stems are brownish-red and the leaves are smaller and dark green. Other variations feature lime-green leaves and red stems with upright growth.