I took a photo of a plant with very nice flowers but unfortunately quite ugly brown spots on its leaves.
I then tried out how the same photo looks if I colorize it (in GIMP it is Colors → Colorize… with Hue 30, Saturation 50, and lightness 0).
As you see the leaves now look much better but the colorful flowers now do not look as bright as they did before. I therefore added a transparent layer to the first image, pasted the colorized version to this layer and then removed the colorized flowers so that the original version shines through. Here is the result of this operation:
Finally I applied some cropping and got:
I like the final result.