Oleander

Edibility: 

NOT EDIBLE. All parts of the plant are highly poisonous.

Toxicity: 

EXTREMELY TOXIC. All parts of the plant (leaves, stems, flowers, roots, sap, and even smoke from burning oleander) are highly poisonous if ingested, and contact with sap can cause skin irritation. It contains cardiac glycosides (such as oleandrin and neriin) that are toxic to humans, livestock, and pets. Ingestion can cause severe symptoms including nausea, vomiting, diarrhoea, irregular heart rhythm, convulsions, coma, and can be fatal. Even water standing near cut oleander branches can be toxic.

Uses: 

Primarily cultivated globally as an ornamental plant for its attractive flowers and evergreen foliage. It is commonly used as a hedge, screen, windbreak, or specimen shrub in gardens, parks, and along roadsides, especially in warmer climates. Its drought and pollution tolerance make it a popular choice for difficult growing conditions.

Ecology: 

As an alien invasive plant in South Africa, Nerium oleander escapes cultivation, particularly along waterways and in disturbed areas. It spreads primarily by its wind-dispersed seeds, which are produced in large quantities. It can also spread vegetatively through root suckers. It forms dense stands, especially along riverbanks and drainage lines, outcompeting and displacing indigenous riparian vegetation. Its extreme toxicity can pose a risk to grazing animals if they consume it. Its ability to thrive in harsh conditions contributes to its invasive success.

Distribution and habitat: 

Widely cultivated as an ornamental throughout South Africa and has become extensively naturalised and invasive in several provinces. It is particularly common in the Eastern Cape (frequently found along roadsides, in urban open spaces, and along riverbanks and drainage lines around Kenton-on-Sea), Western Cape, KwaZulu-Natal, Mpumalanga, Limpopo, and Gauteng. It invades disturbed sites, roadsides, urban open spaces, riverbanks, and drainage lines.

Derivation of name: 

• The genus name Nerium is derived from the Greek word 'neros', meaning "wet" or "damp," referring to its preferred habitat near watercourses in its native range. 

• The species epithet oleander is derived from 'Olea' (Latin for olive tree) and 'dendron' (Greek for tree), referring to its somewhat olive-like leaves. 

• The common name "Oleander" is a direct adoption of its botanical name.

Historical aspects: 

Oleander has been cultivated as an ornamental plant for millennia, dating back to ancient Roman times. It was introduced to South Africa and many other parts of the world as an attractive, hardy garden plant. Its ability to tolerate harsh conditions, including drought and poor soils, and its prolific flowering made it a popular choice. However, its rapid spread via wind-dispersed seeds and its extreme toxicity led to its recognition as a problematic invasive species in many regions globally.

NEMBA status: Category 1b invasive species. This means it must be controlled or eradicated where possible, and it is illegal to plant, propagate, import, or otherwise possess this plant without a permit.

Interesting facts:

• Don't let its pretty flowers fool you! Every single part of the Oleander plant, from its roots to its petals, is super poisonous, even the smoke if you burn it!

• This plant is incredibly tough: it can handle scorching heat, very little water, salty air (like near the coast), and even air pollution, which is why you often see it growing along busy roads!

• Its long, narrow leaves look a bit like willow leaves, but if you break one, you'll see a milky white sap ooze out – that's another sign of its toxic nature!

• Even though it's beautiful, its ability to produce lots of fluffy seeds means it can easily escape from gardens and become a problem plant, especially along rivers where it outcompetes native plants.