I don't worry about small blemishes on the flowers, but there are often spots that need to be touched up; so this is an opportunity to show you that.
I use the eyedropper tool ( I ) to sample the color next to the spot and then use the brush tool (B ) to paint over the spot. That works well much of the time. The healing brush also works, but I find the spot healing tool to work the best ( J ). Simply select that tool and brush over the spot lightly. You may need to use a combination of these to clean up the whole image.
The other shortcut I use is X. With that, you can switch back and forth between the foreground and background colors. It is especially useful with a black & white image, but I often paint or fill 2 colors at a time because this is so helpful.
The healing brush & spot healing brush don't work well near defined edges, so I usually have to use the brush tool in those areas. Quite often, my flower photos will have an insect on a petal, and this method works well for removing them as well. Better than pesticides.