Oleander

Oleander is a shrub or small tree native from the Mediterranean east to southern Asia, widely grown as an ornamental in temperate and subtropical places. Wikipedia describes it as a highly poisonous plant, though its bitterness makes poisoning cases rare, and says it is the only species in the genus Nerium. Cunningham marks it Poison, which in his key means never to be used internally or on the skin. He gives the planet Saturn, the element earth and the power of love, and says it is occasionally used in love spells, never internally. He also records Italian magical thought that keeping any part of it in the house brings sickness, disgrace and misfortune. His other names are Rose Bay, Dog Bane, Ceylon Tree and Adelfa. Wikipedia says ingestion of larger amounts may cause nausea, vomiting, excess salivation, abdominal pain, bloody diarrhoea and irregular heart rhythm, and that prolonged contact with the sap may cause skin irritation, eye inflammation and dermatitis.