Azaleas (Rhododendron spp.
) are evergreen or deciduous flowering shrubs which are a commonly planted ornamental worldwide.
There are over 800 species of Rhododendron spp.
, all with flowers of various colors and are bell-shaped or funnel-shaped. The showy flowers display large, spectacular blooms ranging in colors of red, pink, white, and yellow.
Azaleas and other relatives of rhododendron species contain grayanotoxins (andromedotoxin), and sodium channel activators. Ingestion of 1-2 lb of green leaves can be toxic to horses, and known to cause acute colitis in adult horses. Most cases of poisoning occur in the winter, when there is little available forage to eat or in the summer when there have been frequent droughts, and little pasture available to eat.