Depth of field
Shooting at wide-angle focal lengths creates a much longer depth of field compared to telephoto focal lengths, which is ideal for landscapes as you want as much of the scene as possible to be in focus. To maximize the depth of field, you need to shoot at a narrow aperture too, such as f/11 or f/16, as the narrower the aperture the more of the scene will be sharply in focus.
However, some wide-angle zoom lenses offer considerably wide maximum apertures, such as f/2.8. But if you were to shoot a landscape as such a wide aperture, much of the shot would appear ‘soft’, with only a small slice of the image in focus. Such fast wide-angle lenses are brilliant for astrophotography, though, as they can gather the dim light from distant stars, millions of light years away.