Alien Invasion, Part 3:

Cape Ivy

Cape ivy (Delairea odorata), formerly called German ivy (Senecio mikanioides), is a member of the Asteraceae family (sunflowers) and originated in South Africa. It is a scrambling or climbing herb with soft, hairless, shiny, ivy-like leaves and disk-like clusters of small yellow flowers. At the base of some leaf stems is a small, ear-shaped appendage. Cape ivy's hairless leaves feel smooth to the touch, and the plant has no climbing tendrils. This invasive species is most often confused with the native wild cucumber, which it resembles closely. However, the wild cucumber has rough-feeling, hairy, multi-pointed leaves and curly climbing tendrils. The wild cucumber dies off in the summer and is no threat to the Elfin Forest, having coexisted for centuries. If left unchecked, cape ivy can smother whole groves of trees such as our coastal pygmy live oaks.

Figure 2: Cape ivy (Delairea odorata)

Photo courtesy of Barry A. Rice/ The Nature Conservancy

Cape ivy thrives in coastal plant communities and lowland forest margins, shrub lands, rock lands, roadsides, and house gardens. Cape ivy is an invasive species that has moved into such diverse locations as California, Hawaii, and New Zealand. (In New Zealand the common name Cape ivy has been given to a totally different plant, Senecio angulatus).

The ivy climbs over small shrubs and trees. It can extend up to sub-canopy levels. It hinders plant growth by smothering and out-shading other species. Cape ivy also spreads over large areas of ground beneath the forest canopy, stopping the free regeneration of the ecosystem.

The plant can spread by the wind, moving water, or human activity. Plants grow well in open environments but will germinate in the shade of the forest canopy, near to the margin. The plants spread rapidly by sending out runners.

Because plant breaks when pulled on, the ivy is hard to remove physically. Also, each broken piece, which has a plant node, may produce a new plant if left on the ground during the rainy season. For this reason, it is best to seek out the base of the stem and dig the plant out. Disposal can be by composting or mulching with other plant materials or by physically removing the vines from the locale.

In the home or garden cape ivy can be killed readily by spraying the leaves with Roundup, Rodeo or other herbicide. An appropriate surfactant is needed to penetrate the shiny leaf coating.

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