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Spectacular Spurflowers: Beautiful blooms for the shaded indigenous garden

MRT 22, 2020 | Written & photographed by Zoë C Poulsen

As we bid goodbye to the long and hot days of summer, the weather becomes cooler and our autumn flowering plants start to come into bloom. Coming in a plethora of different shapes, sizes and colours, indigenous shade-loving Plectranthus can light up even the darkest corners of our gardens. Colours vary from white to pale pink to the deepest dark blues and purples.

Plectranthus as Useful Plants

Top: Plectranthus zuluensis ‘White Zulu’. Above: Plectranthus ecklonii ‘Medley Wood’.

This Old World genus of plants are more commonly known as the Spurflowers. They are a part of the Lamiaceae family alongside the mints, sage and basil of the Mediterranean basin. Plectranthus, like these other family members, have a distinct variety of aromas from the vile, skunk-like odour of Plectranthus neochilus, which is believed to scare snakes away from human dwellings, to Plectranthus unguentarius which is used as a deodorising ingredient in the red ochre body lotion of the Himba tribe of Namibia’s Kaokoveld.

In addition, Plectranthus esculentus is also known as the African potato or Unbondwe. This potato-like crop is rich in starch and provides a highly drought tolerant food source. However, the majority of the genus Plectranthus are most well-known for their horticultural value, growing easily in the darkest and shadiest corners of gardens in southern Africa and beyond. As early as 1928 the botanist Edwin Phillips wrote about Plectranthus: “the South African species certainly deserve more attention from horticulturalists than has been given,” and that they make “very fine ornamental shade plants”.

Habitat and Ecology

Top: Plectranthus verticillatus. Above: Plectranthus fruticosus ‘James’.

In the wild, Plectranthus can be found in a variety of habitats, from high altitude grasslands to dry savannas, but most are forest dwellers. They most commonly occupy the forest understorey and are adapted to frequent disturbance by wildlife such as bushbuck and porcupines. There are several species that grow at high altitude in the Drakensberg mountains that have adapted to the cold by re-sprouting from an underground tuber after frost.

Plectranthus in the Indigenous Garden

Above: Plectranthus fruticosus ‘Ellaphie’ flowering en masse at Kirstenbosch National Botanical Garden.

The majority of Plectranthus species make excellent and relatively unfussy garden plants. Those most popular in cultivation come from the Eastern Cape and KwaZulu-Natal. Growth usually takes place during the summer months followed by flowers produced in late summer or early autumn. During the winter months plants can be pruned back to keep the growth neat, maintain vigour and maximise flowering. Plectranthus will also tolerate light frosts if planted under trees.

In gardens they make stunning autumn displays if planted en masse under trees in shaded areas and can be paired with other indigenous genera such as Clivia or Streptocarpus. In contrast, the succulent Plectranthus neochilus thrives in full sun and can be grown throughout South Africa.

How to propagate Plectranthus

Top: Plectranthus madagascariensis. Above: Plectranthus oertendahlii.

Plectranthus are very easy to propagate and can be grown both from seed and cuttings. Seed should be sown in spring in a moist but well-drained growing medium such as two parts compost and sand to two parts loam. Cuttings are best taken during spring and summer with soft tipped cuttings rooting well in moist sand. They should be kept moist and in the shade. During warm weather you can expect rooting to take place within around two to three weeks.

Want to know more?

Beautifully illustrated by botanical artist Vicki Thomas, Ernst van Jaarsveld’s book on the southern African Plectranthus makes for worthwhile and informative reading.

Reference: van Jaarsveld, E. Thomas, V (2006) The Southern African Plectranthus and the art of turning shade to glade, Fernwood Press, Simonstown, South Africa. ISBN 978-1-874950-80-6.