10. Rhododendron
Rhododendron belongs to the same family as azalea and blueberries. The plant has about 1,024 species that grow in thousands of different shapes. It reaches up to 5 to 10 meters in height as it is a woody plant in the heath family. Rhododendron comes in different colors such as red, violet, white, pink, yellow, and blue, as well as in different combinations of those. The toxin is contained in all parts of the Rhododendron, particularly the nectar.