Rhododendron: A large ornamental shrub with large, oblong, smooth leathery evergreen leaves. Toxin is in the leaves and flower nectar. 0.2% body weight of the leaves or 3 ml of the nectar per kilogram body weight is toxic/lethal. Signs include salivation, diarrhea, muscle weakness, impaired vision, slow heart rate and heart block (which may be lethal). Difficulty breathing and depression may also be seen.