Q.Why is my bougainvillea dropping leaves?
We have had a lot of rain. If that’s the cause, will the bougainvillea recover?
Certified GKH Gardening Expert
That can, certainly, be the cause. I would recommend treating for a fungal infection. This article will help: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
I would also recommend applying just a small Teaspoon of DOLOMTIIC LIME and a full Tablespoon of Wettable sulfur. This will help condition the area for the roots, as well as help with infections.
They need to be fed frequently as well. This article will help you with the care of these plants: https://www.gardeningknowhow.com/ornamental/vines/bougainvillea/bougainvillea-garden-care.htm