Oleander is an outdoor shrub, popular for its evergreen qualities and delicate flowers. Found commonly in warm locations (e.g., along highways in Hawaii, California, Texas, etc.), all parts of this plant are poisonous to multiple species such as Bighorn Sheep, Dogs, Cats and other animals in the area. Oleander contains naturally-occurring poisons that affect the heart, specifically cardenolides or bufadienolides. These poisons are called cardiac glycoside toxins, and they interfere directly with electrolyte balance within the heart muscle. The following plants are known to contain glycosides.
These beautiful plants are on of the many dangers that threaten the Desert Bighorn Sheep that is on the brink of extinction. Since August 2012, there have been 12 reported bighorn deaths in La Quinta, including the five lambs that have died since May 6. Four of the sheep drowned in the concrete-lined Coachella canal; one was struck by a car on Jefferson Street; one died from oleander poisoning at PGA West; and one died from disease.
Bighorn sheep getting killed on Highway 111, drowning in swimming pools and dying from oleander poisoning led the city of Rancho Mirage to build a 4.5-mile long, 8-foot-high fence – constructed of material that blends into the environment – about 15 years ago at a cost of about $1 million.
There are ways you can help stop the deaths of bighorn sheep such as keeping domestic animals away from places that bighorn sheep reside. Also you can remove Oleander from your property and replace it with another shrub that is local or even suggest neighbors to take down their oleander.