Use the lasso , or the pen tool to select the flowers now you don't want to ruin it if it goes wrong. So just copy the layer and now right click and select inverse.
Now every thing in the second layer is selected except the flowers press delete.
Go to back layer and press CTR L+SHIFT+U this will cause an desaturation now. Go to the parent layer
and play with the blending modes to produce cool effects.
and if the color blending or the lights don't suit you simple. use the blur tool to get them nice and smooth.
