Nerium Oleander: The Beautiful Killer Plant
Nerium Oleander Plant
You have probably crossed paths with this plant multiple times, and maybe even admired its beautiful flowers, but are oblivious to its dangers. Nerium oleander, known in Lebanon as “difleh”, is a flowering shrub that is widely cultivated in temperate and subtropical areas. It is used as an ornamental plant as well as for landscaping purposes, and is believed to be native to the Mediterranean area.
One interesting fact about this common plant is that in order for the flowers to set seeds, they require the visit of a pollinating insect. The flowers do not contain nectar, though, and they offer no reward for the visiting insects. Unsurprisingly, then, they do not receive as many visits as many other similar species do.
Nerium plants, when trained to a single trunk tree, can grow up to 6 meters high and create a medium sized canopy that provides a calming shade for commuters. Lebanon is one of the countries using this plant to decorate urban spaces such as sidewalks, public gardens, and other public areas. In addition to creating shade, it is chosen for its attractive pink, white, red, or yellow flowers and its renowned ability to withstand hot temperatures. Moreover, it is extremely drought and flood tolerant, though it is easily killed by long periods of frost. In other words, it’s a beautiful and famously easy plant to grow and maintain, requiring very little irrigation and care, making it ideal for outdoor scenery.
At least, it’s almost ideal. It has one “small” problem: it is extremely poisonous.
Nerium Oleander in the streets of Jounieh, Lebanon
One must assume either that none of the governmental and municipal institutes or plant dealers have had the diligence of researching this plant before planting it in public spaces, or that they are aware of its lethal potential and have planted it without going through the trouble of installing multilingual signs to warn the public of its danger.
Here’s a little background about the toxicity of this decorative shrub.
Nerium oleander can be fatal to both humans and animals. It contains several toxic compounds, and it has been described as 'an extremely toxic plant’ (1). If as little as 0.005% of an animal’s body weight in dry Nerium oleander leaves is ingested, it can be lethal (2). According to Dennis Blodgett, a Virginia Tech toxicologist, “of the thousands of poisonous plants known to scientists, oleanders are one of the most toxic and potentially lethal” (3).
The flowers, leaves, and twigs are all deadly. In Siri Lanka for example, committing suicide using Oleander has been common for generations; death is achieved by boiling the leaves into a “suicide tea” and drinking it (4). Accidental animal and human deaths from oleander worldwide still happen to this day, sometimes when unsuspecting by-standers make the devastating mistake of brewing a tea out of the flowers, or by using the fallen dry twigs for cooking over a fire and passively inhaling the fumes, or by other such unknowing errors.
Recorded death incidents of human toddlers or animals have happened as early as 45 minutes after ingestion. (2) The toxic dose of oleander is estimated to be 45 mg/kg of plant per body weight for cattle, equivalent to 12 average-sized leaves. In one study, a heifer that was given 1g of plant/kg of body weight died within 45 minutes from ingestion. If a small child eats one green leaf, it may be enough to kill them (2); and if a small to medium sized dog eats one to two dry clippings (leaves) from the ground, it would be enough to kill them as well.
Symptoms of Nerium Oleander poisoning may include: nausea, vomiting, excess salivation, abdominal pain, bloody diarrhea, and irregular heart rhythm. Prolonged contact with sap may cause skin irritation, eye inflammation, and dermatitis.
Growing this plant in parks and public areas where we encourage our children to explore freely is, quite simply, dangerous and irresponsible. While the plant has been used for shade and decoration for generations, our knowledge today compels us to treat the matter with due caution and ensure the prevention of accidents. Better planning needs to keep these plants limited to spaces where children and pets are reasonably unlikely to venture (especially unsupervised), and signs must be placed to clearly warn the public of its dangers.
References:
(1): https://www.sciencedirect.com/science/article/pii/B032301125X500285
(2): https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/nerium-oleander
(3): https://www.dailypress.com/news/dp-xpm-19920823-1992-08-23-9208230016-story.html
(4): http://www.gibraltarpanorama.gi/176522#:~:text=In%20South%20Asia%2C%20particularly%20Sri,as%20'an%20extremely%20toxic%20plant
