The Giving Garden – Rethinking the food-medicine continuum in the urban sprawl

South Africa’s recent performance in several international horticultural exhibitions has proven once again that our botanical diversity holds great value in the world of ornamental horticulture and our nation’s bioeconomy. However on top of the dazzling aesthetic displays, the diverse range diverse range of edible and medicinal plants presents valuable opportunities to ensure future food security and health. In this new series, The Giving Garden, we will be showcasing species that we believe should be incorporated into urban plantings and the wider South African agricultural system. The series is an extension of our work at the University of Pretoria’s Manie van der Schijff Botanical Garden, specifically the Future Africa Indigenous and Orphan Crops Collection, looking at the role that these underutilised edible and medicinal species can play within society. The series carries the same name as one of our teaching and learning spaces, The Giving Garden, which is used to expose students to agrobiodiversity and provide propagation material of these crops to community food gardens. It is thus fitting that this journey starts in the grasslands of Gauteng with a species that has received much attention from the scientific community as a climate-smart crop: Tylosema esculentum.

Marama beans (Tylosema esculentum) are a long-lived perennial legume indigenous to most of Southern Africa. The species is easily recognisable in the veld by its long, trailing stems which extend for several metres into the surrounding grasses. Below the soil surface the plant forms a large tuberous storage root from which it can draw moisture during periods of drought, giving the species a high tolerance to adverse conditions. Bright yellow flowers make the plants easy to spot in early summer. The flowers form tough brown seed pods, each typically producing one to two large beans. Both the tuber and the beans are edible, with beans having both a high protein (32%) and oil (36–43%) content. Beans have a nutty flavour and can be roasted, boiled, or ground into a flour.

Marama beans growing between the rubble of an illegal

dumpsite in the City of Tshwane

Conversations around the future of food security have only fairly recently begun to focus on crop wild relatives and the use of alternative crop species, and there is an urgent need for ecologists and agriculturists to close the gap between the our respective fields, as wild populations of edible plants continue to shrink and experience a rapid loss of unique genetics in the face of the global land squeeze. Part of our work at the Manie van der Schijff Botanical Garden is safeguarding the genetics of populations under threat, and the seeds collected from the edges of the illegal dumpsite will be used to establish a new planting of marama beans on the Future Africa campus, a transdisciplinary research campus of the University of Pretoria which houses the majority of the indigenous and orphan crops collection. This planting forms part of our continual expansion of our collection of indigenous edible plants, as well as safeguarding the genetics of populations under threat.

Marama beans are incredibly easy to grow and the species has a relatively high germination rate. In our experience, seeds should be scarified but not pre-soaked, as soaking typically increases losses to diseases such as damping off. Scarification is most practically done with a file or rasp, although a gritty sandpaper can also be used. The species grows best in well-drained soil in full sun, and should be kept as dry as possible during its winter dormancy. Because of its high drought tolerance, the species is well suited to dry spaces where other food plants would struggle. The trailing nature of the stems makes the species a fantastic addition to urban gardens, as the stems can be redirected to form a thick living mulch. While we at the Manie van der Schijff Botanical Garden have begun increasing our propagation capacity to make edible plants like the marama bean more accessible to home and community food gardeners, ethically-sourced seeds are currently already available from Living Seeds.

Incorporating edible plants into urban plantings does not have to make maintaining these spaces more difficult, and species like marama beans tend to look after themselves. Our hope with this series is to provide practical examples of species we work with directly for BotSoc members to consider growing. If there are particular species that you would like to see featured, or specific information you think should be included in this series, please don’t hesitate to reach out to us.

Richard Hay
Curator: Future Africa Indigenous and Orphan Crops Collection, Manie van der Schijff Botanical Garden, University of Pretoria
BotSoc Conservation Project Coordinator, Northern Region
richard.hay@up.ac.za or north@botanicalsociety.org.za

Jason Sampson
Head Curator: Manie van der Schijff Botanical Garden, University of Pretoria
jason.sampson@up.ac.za