It’s been a hothouse now for years, at a large botanic gardens. I never expected it to fruit, just a nice looking plant and small pretty flowers.
I’m no botanist, but the only thing I can think of is the quality of sunlight. While the desert in California, Arizona, and parts of Texas is hotter than here (even though all are farther north), the sun here is like nothing I’ve ever seen before in my life. That strength of sun may be needed for these plants to fruit. That’s the only thing I can think...