The reasons why there are multiple oleandro trees at our highways often planted oleandro trees. The main ones have to do with road safety: being poisonous, the oleanders keep animals at a distance, which instinctively do not approach and, therefore, do not cross the roadway. In addition, oleanders can act as a natural barrier in the event of an accident. Other reasons are linked to the fact that the oleanders need little maintenance and can resist for prohibitive climatic conditions, which makes them very cheap. Finally, the oleanders, attracting insects with their flowers, contribute to the maintenance of biodiversity.
Road safety
Along the highways we often see oleandro trees (Nerium Oleander), are planted on the edge of the roadway or in the center, with functions of dividing. The reasons for their presence are not exclusively aesthetic: on the contrary, oleanders are planted for reasons linked mainly to road safety and ease of maintenance.
Oleanders are highly toxic plants for both humans and animals. We know, for example, that some soldiers of Napoleon’s army during the Italian countryside died of poisoning after using oleandro branches as skewers to roast the meat. Being toxic therefore, they keep the wildlife far away: the animals instinctively held at a distance and, consequently, the risk that they cross the roadway and cause accidents significantly reduces. This feature is particularly useful at night, when visibility is reduced and motorists may not see any animals on the road on time.
Furthermore, the oleanders are also useful for road safety for another reason: thanks to their thick hair, if they are arranged in hedges they can act as a natural barrier, managing to cushion the impact of vehicles in the event of an accident. In fact, they absorb a part of kinetic energy and in this way reduce the damage caused by the impact. Furthermore, if placed in the center of the roadway as a sparotraphic, they also act as a barrier for the dazzling headlights of the vehicles that proceed in the opposite direction.
Practicality and support for biodiversity
Other reasons for the presence of oleanders on the highway are linked to the resistance and ease of maintenance of the plant. The oleanders are in fact equipped with great resistance and can survive in prohibitive climatic conditions, which allows them to bear the warmth that emanates the asphalt on the hottest days. They also need little maintenance: there is no need to water them regularly and, consequently, the cost for entities that manage the highways is very reduced.
Finally, oleanders have the function of contributing to the maintenance of biodiversity: although being toxic, their flowers attract various species of insects, thus favoring biodiversity in prohibitive areas for animals such as motorways.
