Even the post-apocalypse can be beautiful, under the right circumstances.
Commonwealth HQ Landscape Overhaul is a mod created by a Nexus mod member known as Printerkop, and you should definitely check it out. As the name implies, it re-does the textures for Fallout 4's terrain, and the changes are pretty noticeable! The shrubbery is more distinct, there's a wider variety of terrain and rock, the soil is better, leaves look crunchier, hell, even the garbage looks more realistic.
Here's a great video by hodilton, showcasing it in action:
Or, if you'd like to see more of a before/after video, Wilsonator has got your back:
Wilsonator notes that the overhaul mod doesn't really cause performance issues, which is great news.