Mood is not as easily definable as it is in genres that involve a living subject displaying emotions for the viewer to see, but it is still possible to convey feelings in a landscape image with just as much power as something like a portrait. This great video discusses the process of adding mood to landscape images.
Coming to you from Nick Page, this excellent video discusses the process of adding mood to landscape photos. Unlike genres where you get the benefit of a human or even animal subject who can clearly embody readily readable emotions, landscape photography is more nuanced, as you have to find other ways to convey a certain feeling or mood. This is actually one of my favorite things about the genre, as I enjoy the challenge of using objective, quantifiable parameters to evoke subjective, sometimes nebulous feelings. Learning to connect post-processing techniques with moods in your mind will go a long way in helping you to realize your creative visions. Check out the video above for the full rundown from Page.
And if you really want to dive into landscape photography, check out "Photographing The World 1: Landscape Photography and Post-Processing with Elia Locardi."