There are two concepts here.
1/ Landscape photography is taking photos of the landscape, sometimes you want a 90deg field of view, sometimes you want 10deg field of view. You can use any lens.
Wide angle lenses fit more in and have a greater depth of field. Often this leaves too much boring scenery in the photo and you'll find cropping the photo to a letter box format works really well. Telephoto lenses bring distant object closer (called compression) and give you the option to have parts of the image slightly out of focus to give you a 3D feel. Often Portrait Orientation works well.
2/ Difference between wide angle/normal/telephoto.
There are two considerations, magnification and field of view.
I consider Magnification (which is affected by your viewfinder) to be a better definition for landscape photography where as field of view is more critical to human portrait photography
For me a normal lens is one that has normal magnification when viewed through you viewfinder, ie 35-50, Wide angles shrink the image and telephotos magnify the image. FF and APS-c are the same for each focal length in this regard with APS-C being cropped.
In portrait photography the critical part is your distance to the subject so the angle of view is the important part. If you get to close to your subject they will be distorted.
For portraits lenses we should actually define the lens by the amount of subject to be captured, ie group portrait, full body , upper torso, head shot, long distance. In this regard the focal length required is 1.5times longer for FF vs APS-C
A couple of landscape shots to show you some differences.
14mm, photo shows benefit of depth of field with wide angle, Often you need foreground objects to make them work
14mm, semi letterbox crop. too much sky and water without cropping
100mm, less depth of field, foreground and background slightly blurred gives depth to the image.
100mm, portrait. compression draws you into the scene.