African Wildlife & Environment Issue 84 2023

GARDENING FOR BIODIVERSITY

Erythrina caffra flowers with their broader petals and ‘whiskery’ appearance (Photograph: C Botha)

which are longitudinally four-winged. Introduced as a garden ornamental, probably only within the last 50 years, it has now replaced indigenous vegetation along a considerable length of many of our rivers. This restricts the flow of water during flooding, thus leading to erosion of riverbanks. Various parts of the plant have been shown to be lethal to many creatures, including humans, sheep, chickens, ducks and even sparrows. Because the disadvantages of this poisonous invader far outweigh its undoubted attractiveness as a garden plant, it has quite rightly been outlawed as a noxious weed. Flowers of Erythrina species are designed to be pollinated by birds and, as they mature in sequence up the spike, there is always a fresh supply of nectar available. In addition to the many flowers the nectar is extremely abundant, some individual blooms holding as much as ten drops. Many species of sunbirds, as well as other nectar-loving creatures, continually frequent these flowers. The beautiful Malachite Sunbird, being quite partial to flowers of E. zeyheri , is easy to watch as it forages because of the small size

The summer-flowering Erythrina humeana is usually a shrub or small tree (Photograph: C Botha)

43 | African Wildlife & Environment | Issue 84 (2023)