Oleander/ˌəʊliˈændər/ Definition 1 of 1Pro Tip 1/3Toxic Caution Emphasize oleander's toxicity to highlight its danger in conversation or writing. The oleander looks innocent, but even a small amount can be deadly. Pro Tip 2/3Warm Climates Use 'oleander' when describing vegetation typical in warm, sunlit environments. Oleanders thrive alongside the palm trees in this coastal area. Pro Tip 3/3Landscaping Mention Mention oleanders when discussing garden plants for their decorative flowers. For a splash of color, consider adding oleander to your backyard.