Oleander blooms in summer. It was reportedly introduced to Japan via Nagasaki  in the mid-Edo period.

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The trees are resistant to drought and air pollution, and are used as roadside trees and fire prevention trees. They are planted around schools and parks because they reduce the effects of noise and exhaust gases and can be used as buffer zones to prevent dust and sand scattering. Oleander is said to have grown quickly in polluted or bombed areas, while other trees declined or died.

(Oleander is known as the first flower to bloom in the A-bombed city, where it was said that no plants or trees would grow for several decades.)

 

Oleander contains a toxic substance called oleandrin. All parts of oleander are toxic . There have been deaths caused by oleander abroad in the past. The soil around oleander remains toxic for at least one year after it is decomposed.

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On the other hand, oleander poison is also used in medicines (the strong cardiac glycoconjugate in the leaves and bark is the source of medicinal cardiotonic and diuretic agents). It is often used as a roadside and fire prevention tree because it is believed to purify the atmosphere by opening and closing the pores on the underside of its leaves.

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Recently, there have been many calls for the removal of oleander in light of its toxicity.  Oleander itself has remained unchanged until now. It exists with extraordinary vitality wherever it is.