Any of the ornamental evergreen shrubs of the genus Nerium (dogbane family), which have poisonous milky juice. Numerous varieties of flower colour in the common oleander, or rosebay (N. oleander), have been introduced from greenhouse culture and are grown outdoors in warmer climates. All parts of the plant are very toxic if eaten, and contact with them may cause skin irritation.

Learn more about oleander with a free trial on Britannica.com.