How To: Turn Green into Yellow - shades of Yellow, bright, mustard, green-yellow

I appreciate the replies. My statement was directionally correct - I want it to look like fall; however I was not asking for the "perfect REAL" fall. I wasn't asking for PS to create leaves on the ground. I wasn't asking for PS to create a level of wetness or dryness that may or may not exist in fall (depending on the location, year, weather and 1,000 other factors).....  I JUST want to be able to turn greeen leaves, or a selection of some green leaves - yellow,  and really any shade of yellow.

Here's a sample for you:

If this is about actually making it look like fall, simply changing the color won’t look convincing. The changes to the leaves go far beyond color. A green spring/summer leaf has a relatively even color texture, and can look soft and well-hydrated. In the fall, the same leaf dries up, so the texture changes significantly. It gets brittle and develops crinkles, cracks, holes, and dark spots, and bits flake off it. It can become multi-colored, like yellow to red, in a way that’s splotchy, uneven, and can change toward the edge. All of that changes how light reflects off of the leaf, so the tonal quality is no longer the same as when it was living and green.

Given all that, if you wanted to create a convincing fall version of a leaf, changing only the color will look fake if all of the other changes are missing: Changes to tonal range, surface texture, and the damage of decay.

Taking a different approach, you could try just sliding the Autumn option in the Landscape Mixer (choose Filter > Neural Filters) as shown below, but this will probably alter the content detail of the image in ways you might not want. There might also be a way through Generative Fill, but I haven’t figured that out.

In addition to Hue/Saturtion,  did you try Image>Adjustments>Color Balance?  Try that and then go back to Saturation

This isn't just color, it's brightness. Yellow is inherently much brighter than foliage green. It has to do with our visual sensitivity to different wavelengths.

If you want to quantify the difference, the Lab color mode takes this into consideration. Make two samples of summer green and fall yellow, and compare the L values.

In other words, this is a lot more tricky than it sounds. It's basically analogous to the very frequent question we get here about changing the colors of garments. And the answer is that the whole tone curve needs remapping, not just the color. Only here you have to do it to parts of the image, not the whole.