Will a Nikon 55-300mm af-s take good landscape shots?

Reason i'm asking is because i plan to get this lens and a 50mm and wonder if I have to dedicate landscape photos to the 50mm or if both will work ok

Only if you're far enough away, that's what the 18mm end of your 18-55mm is for.

Not sure I understand your question. You can take any types of photos with any lens but if you want to zoom in and take photos, the zoom lens with help. Many professionals as such take landscapes with wide lenses (which are usually smaller than 50mm).
If you want to take good landscapes, tripod can be very useful to take low aperture photos to keep most things in focus. Also, most of the amazing landscapes are taken in the low light of early mornings or during evenings and a tripod can help much more to take sharp photos. If you are not using Tripod, you can use a fast 50 mm lens too in many situations.

I have the 55-300mm which I like but honestly never use that much. The 55mm wide end of that lens is not good for landscape shots because its too narrow. Its good for subject isolation but that's really it.

If you photograph a distant mountain range or something like that at 55mm then it might workout.
Your 50mm won't be any better for landscapes.

What you need is a lens with a wider angle. Like the 18-55mm kit lens or even better the Nikon 16-85mm lens. Which is fantastic BTW. With the 16mm wide end of that lens you can pretty much get everything you want in the shot. The 16-85mm is what I use probably 60% of the time I'm out taking pictures.

It's not really a landscape lens. A better choice would be the Tokina 11-16mm DX2 (make sure you get the DX2 version if you have a D3xxx or D5xxx or it will not autofocus).

Here is a webpage showing what different zoom lengths look like:

http://www.althephoto.com/concepts/lenses.php

As a general rule landscapes are done using a wide or ultra wide angle lens. The 18mm end of your 18-55mm zoom makes an acceptable focal length for landscapes but an even wider lens would be even better. 50mm or 55mm is simply not wide enough for landscape photography in my opinion unless your subject is, maybe, the Grand Canyon.

I suggest looking at the AF-S DX Nikkor 10-24mm f3.5-4.5G ED for landscapes.

I consider a tripod as mandatory for landscape photography.

Although most people assume that setting a wide angle lens like the 10-24mm to f16 and infinity will maximize their depth of field it actually won't. There are only three factors that affect your depth of field (DOF):

1) The focal length of the lens.
2) The aperture used.
3) The subject distance.

From experience I know that by setting the Distance Scale (a feature sadly lacking on many modern lenses but available on the AF-S 10-24mm lens) on my 17mm lens to 6'-0'' and using f16 my DOF will be from 1'-8'' in front of my camera to infinity. I also know that setting the lens to infinity focus will decrease my DOF to 2'-1'' in front of my camera to infinity. Granted, 5'' isn't a lot but its still less DOF at infinity than it is at 6'-0''.

You can use the DOF Calculator at this site - http://www.dofmaster.com/dofjs.html - to compute your DOF for any combination of the three factors imaginable.

Computed using a Nikon cropped sensor camera:

10mm @ f16 with Distance Scale at 6'-0'' DOF is from approximately 11'' to infinity.

The AF-S 50mm f1.8G is great for low-light, non-flash photography plus it makes a good portrait lens on your camera.

Landscape shots are about wide open spaces. Think of the Grand Canyon or the whole expanse of the Golden Gate bridge. The best lenses for those type of shots are called wide angle lenses. They see more than your eyes from side to side and make the subject smaller in the picture.

For APS-C cameras, wide angle starts at around 23mm going down. If you have the 18-55mm kit lens, the 18mm end is wide angle. For full-frame cameras, wide angle starts at around 35mm.

50mm is telephoto meaning it sees less than what your eyes can see and make a distant object look closer to you. This means both 50mm and 55-300mm won't be good for taking landscapes.

http://keerok-photography.blogspot.com/2011/05/lenses-so-many-of-them-there-is-no-best.html