Cape Ivy

Delairea odorata is native to South Africa, specifically the Western and Eastern Cape provinces, where it grows in moist coastal forests, along stream banks, and on forest margins from sea level to approximately 1,000 meters elevation.

• Found naturally in the Afromontane and coastal forests of the Cape Floristic Region, one of the world's most botanically diverse areas
• The genus Delairea is monotypic, containing only this single species, which was formerly classified in the genus Senecio (the enormous ragwort genus with over 1,500 species)
• Introduced to Europe as a glasshouse and conservatory ornamental in the mid-19th century, where its rapid growth and glossy foliage made it a popular Victorian parlor plant
• Escaped cultivation in multiple regions and is now naturalized and invasive in coastal California, Oregon, Hawaii, Australia, New Zealand, and parts of Mediterranean Europe
• In its native South Africa, the plant is a well-behaved component of forest ecosystems, kept in check by natural herbivores and pathogens that are absent in its introduced ranges
• The species name odorata refers to the sweet fragrance of the flowers, which is unusual in the Senecio alliance and helped distinguish it as worthy of its own genus

Stems: Slender, twining and scrambling, 3-6 m long, green to purplish, hairless (glabrous), slightly succulent, producing roots at nodes where stems contact soil or moist surfaces, 2-4 mm in diameter.
• Stems are smooth, fleshy, and easily broken, with every fragment capable of rooting
• Internodes are 3-8 cm long, giving the vine a rapid coverage rate

Leaves: Ivy-shaped (cordate with 3-5 angular pointed lobes), 3-10 cm long and 3-8 cm wide, fleshy, glossy bright green above, slightly paler below, palmately veined with 5-7 prominent veins, margins with small rounded teeth, petioles 2-5 cm.
• Leaves are succulent and store water, enabling drought tolerance
• The ivy-like shape is a remarkable example of convergent evolution with true ivy (Hedera helix)

Flowers: Small, bright golden-yellow, in dense terminal corymbose clusters 3-6 cm across, each flower head composed entirely of disk florets (no ray florets) 5-7 mm long, sweetly fragrant.
• Flowering occurs from late autumn through spring (May-September in the Southern Hemisphere)
• The sweet fragrance is distinctive and fills the air near blooming plants
• Flowers attract a wide range of insect pollinators

Fruit: Achene with pappus (cypsela), 2-3 mm long, ribbed, with white bristly pappus for wind dispersal — rarely produced outside its native South African range.
• Reproduction in non-native ranges is almost entirely vegetative

Habitat: Native to moist coastal and Afromontane forests of South Africa's Cape Floristic Region. In invaded ranges, colonizes riparian corridors, coastal forests, moist canyons, and shaded slopes. Thrives in USDA zones 9-11, preferring cool, moist, fog-influenced coastal habitats.

Invasive Impact: One of the most significant invasive species in coastal California, where it infests riparian corridors from Monterey to Humboldt County. The vine forms dense curtains that completely blanket native vegetation, blocking light and killing understory plants, shrubs, and even small trees. Riparian bird populations decline dramatically in Cape Ivy-infested areas due to loss of nesting habitat and food plants.

Dispersal: In non-native ranges, spread is almost entirely vegetative — stem fragments are transported by water along streams, by animals, on machinery, and in garden waste. Even a single-node fragment can start a new infestation. Seed production is rare outside South Africa, so the plant's invasion is driven entirely by vegetative cloning.

Biological Control: The gall-forming fly Parafreutreta regalis, native to South Africa, was approved for release in California as a biological control agent. The fly larvae form galls on stem tips, stunting growth. The South African rust fungus Puccinia lagenophorae is also being investigated as a potential biocontrol agent.

Chemical Ecology: Contains pyrrolizidine alkaloids that are toxic to livestock and may contribute to its success as an invasive by deterring herbivory in its introduced range.

WARNING — Cape Ivy should NOT be planted outside its native South Africa. In regions where it is invasive (coastal California, Hawaii, Australia, New Zealand), it is a serious environmental threat.

Control and Eradication: Removing established Cape Ivy infestations is extremely difficult and requires persistent multi-year effort. Manual removal must capture every stem fragment — any piece left behind will regenerate. Solarization (covering with black plastic for 3-6 months during hot weather) can be effective for small patches. Systemic herbicide (triclopyr or glyphosate) applied to actively growing foliage is the most practical approach for large infestations, but requires follow-up treatments over 2-3 years.

Responsible Alternatives: For similar ornamental foliage, consider native alternatives. In coastal California, plant native wild cucumber (Marah fabacea), native honeysuckle (Lonicera involucrata), or native morning glory (Calystegia occidentalis). In other regions, consult local native plant societies for appropriate substitutes.

If Growing Indoors: If already growing Cape Ivy as a houseplant, be extremely careful with disposal. Never compost or dump garden waste containing Cape Ivy near waterways or natural areas. Dispose of all plant material in sealed bags in household waste. Do not share cuttings with other gardeners.