How Toxic Is Oleander to Humans?

Oleander (Nerium oleander) is an evergreen shrub or small tree that is prized by home gardeners for its showy, funnel-shaped blooms. Hardy to U.S. Department of Agriculture plant hardiness zones 8 through 10, oleander is part of the Apocynaceae or dogbane family. Oleanders are fast-growing and easy to care for, which makes them an appealing landscape plant.