I have Yellow Oleanders (Thevetia Peruviana) in my garden in Thailand. Different trees produce yellow, salmon pink and white blossoms. The amazing thing is that over the three years that they have been producing flowers, they have bloomed every single day without exception. At night, all the flowers fall off (making quite a mess on the ground) but in the early morning new flowers are produced. I calculate that one tree over the three years produces about 100,000 flowers. Has anyone else had a Yellow Oleander that flowers 365 days a year?