"Environmental Guardian" Is Oleander Poisonous? Can It Be Grown Indoors? When Does It Bloom?

Oleander, also known as Bitao, Baiyangtao, Jiujiezhong, Liuyetao and so on, is often cultivated in parks, scenic areas, along roadsides, and around rivers and lakes. So is oleander poisonous? Can it be grown indoors? When does it bloom?

Oleander is native to India and has strong adaptability, so it was widely introduced around the world very early on. Oleander is an evergreen erect large shrub of the genus Nerium in the dogbane family, reaching up to 5 m tall, with grayish-green branches; young branches are angular and slightly hairy, losing their hair when old. Leaves are in whorls of 3-4, dark green on the upper surface and light green beneath, with the midrib sunken on the upper surface and flat petioles; the cyme is terminal, and the corolla is deep red or pink. When the corolla is single-layered and 5-lobed, it is funnel-shaped, and the seeds are oblong.

Is oleander poisonous?

Oleander was first introduced and cultivated as an ornamental garden plant during the Tang and Song dynasties, but what made it most famous worldwide was not its delicate, beautiful flowers, but its toxicity.

The entire oleander plant contains extremely strong toxins that can cause death in humans and livestock, and there have been reports of death from small amounts. The whole plant contains multiple toxins, of which the most abundant are cardiac glycosides. The leaves, bark, roots and pollen of oleander are all toxic, with the highest concentration of toxins in the sap. The milky white sap it secretes is rich in oleandrin, and accidental ingestion can easily cause poisoning. Even more astonishing is that the toxicity of oleander persists even after the plant dries out, and the smoke produced when it is burned is also highly toxic.

Symptoms of oleander poisoning

Oleander poisoning mainly presents as digitalis poisoning symptoms, and may include nausea, vomiting, abdominal pain, diarrhea, slow heartbeat or tachycardia, and arrhythmia, and may be accompanied by fever, difficulty breathing, cyanosis, blurred vision, and red rash around the mouth, finally followed by fainting, convulsions, coma, and ectopic heart rhythms; an electrocardiogram may show bradycardia, conduction block and various other types of arrhythmia, and death often results from ventricular fibrillation and circulatory failure.

Therefore, although oleander is beautiful, it is still not suitable for widespread use as an ornamental flower, especially for home gardening, so it is not recommended to grow it indoors. When viewing this flower, do not touch the white sap secreted from the flowers, stems and leaves. Children should also be educated and told not to pick or chew the flowers and leaves casually.

So if this oleander is poisonous, why is oleander still planted?

Because oleander is one of the plants with the strongest dust-absorbing capacity in the world, and is known as a natural “green vacuum cleaner.” It has a very strong ability to absorb and resist harmful gases such as sulfur dioxide, chlorine and hydrogen fluoride, and can also retain smoke and dust; even if its whole body is covered with dust, it can still grow vigorously. According to measurements, a potted oleander at 40 m from a pollution source suffered only slight damage, and at 170 m it was basically unharmed and could still bloom normally, with the sulfur content of its leaves more than 7 times higher than that of unpolluted plants. Even if oleander is covered all over with dust, it can still grow vigorously, and people call it the "Environmental Guardian."

When does oleander bloom?

Oleander has a long flowering period, blooming almost all year round, with the peak in summer and autumn; the flowers are delicate and beautiful. Whenever the flowering season comes, it produces dense clusters of white or peach-red flowers, decorating our cities. Every time it blooms, it always attracts crowds to take photos together, and some even pick the flowering branches for young children to play with. In fact, this kind of “close contact” with oleander is very dangerous.

Reminder: When facing this beautiful “Environmental Guardian,” please keep your distance and never play with it up close.