LANGUAGE AND MEANING OF FLOWERS AND PLANTS
The oleander, due to the fact that its leaves are arranged in groups of three, it symbolized the harmony of the universe in ancient times, formed by triads which as Pythagoras stated "is the existence in which the Immutable and the Mutable are conjoined".
That its meaning was in the past a good omen is also testified by the fact that in the Middle Ages an ancient legend narrated that on the stick of St. mace of St. Joseph.
Later though the oleander from a good luck symbol has become a funerary symbol, both in the Mediterranean countries and in the Middle East. Why there was this reversal is not known, perhaps due to the fact that it was discovered that it was a poisonous plant. Pliny wrote "he kills snakes and when approached with a wild animal causes it to numb". Apuleio also narrates in the metamorphosis that Lucio, after being transformed into a donkey while he was looking for a rose plant that could restore his human features, was about to exchange the oleander with the rose but as soon as he realized the difference he ran away. The nickname "horse killer" or "donkey killer" probably derives from here.
Many sayings were born in Venice around the oleander all related to a plant that brings misfortune as in Tuscany in ancient times the dead were covered with its flowers, a widespread custom also in Sicily.