Why Are The Flowers On My Mandavillia Dropping

Question

leaves turning yellow and dropping, flowers bloom then drop

Answer 1

There are a few reasons why this could be happening. Testing your soil will, likely, help. The pH could be too low or too high. The soil could be too moist. Soils that remain too moist will suffocate roots and invite disease. Alternatively, underwatering can cause this, as well.

I suspect nutrient deficiency in the soil. This can be tested for and corrected. Here are some articles that will help:

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm

https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm

https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-disease-problems.htm

https://www.gardeningknowhow.com/ornamental/vines/mandevilla