When i got my begonia plant a year ago it was covered in bright pink flowers. It’s still in the original container in my living room. I pruned it back last fall and it quickly grew back. It’s starting to get flower buds now, but they’re white instead of the pink I loved. I’ve been feeding it some Bloom Plus when I water it. Is there any way to change the color?
Most of the time, this is a natural occurrence with age of the plant. Sometimes it can be an indication that they need more light. This article will explain what's happening in more detail: https://www.gardeningknowhow.com/plant-problems/environmental/fixing-color-faded-flowers.htm
This collection of articles will give you more information on the care of Begonias: https://www.gardeningknowhow.com/ornamental/flowers/begonia/