If you are trying to accomplish this in LR/ACR with HSL, try using the "aqua" slider instead of blue - slide the luminosity aqua slider to -100. The effect is more natural, tonally, and there are no artifacts. Skies are not "blue" sort of cyanish - why HSL has sliders like "aqua" and not "cyan" is puzzling.
Anyway, give it a shot. The sky darkens, but does not look overly compressed. The attached 100% crops are with ACR sharpening set to Amount 50, radius 1.0, detail 65, masking 55 (tending toward light deconvolution-like sharpening) to see if aggressive capture sharpening would accentuate artifact from this HSL move. The small, complete image is from PS, reduced to 1600 px on the long edge, using bicubic - not output sharpening - try with the file and get it into the format you will use and then apply you sharpening to see if the edges at the sky-leaf borders can withstand this technique.
EDIT - you can also use the blue luminance slider to further darken, up to about -25, still with no halo edges; however, at that point the sky is unnatural in tone.
You can also set the combination of tonal controls in raw conversion to get the sky looking the way you want and then apply local modifications to the other elements for which it may be easier to build masks.