
My Canon landscape lens recommendations ...
Canon EF-S 10-22mm f/3.5-4.5 USM Lens
(EF-S mount only)
Canon EF-S 17-55mm f/2.8 IS USM Lens
(EF-S mount only)
Canon EF 17-40mm f/4.0 L USM Lens 
Canon EF 24-105mm f/4.0 L IS USM Lens 
Canon EF 70-200mm f/4.0 L IS USM Lens 
Canon EF 70-200mm f/4.0 L USM Lens 
Canon EF 24mm f/1.4 L II USM Lens
Narrowing down the lenses to recommend for the landscape category is not easy.
Most lenses out there, from a 15mm fisheye to a 600mm Super Telephoto, can be used for landscape photography.
Many of the lenses in my General Purpose Lens Recommendations make excellent choices.
Value, versatility, image quality and physical attributes are the features I am looking for in a landscape lens.
Most landscape photography is done using small apertures for a desired large DOF (Depth of Field).
So, while landscape photography does not need the fastest lens, it does need very good optics to capture the tiniest details.
The 17-40, 17-55, 24-105 and 70-200 are not large or heavy (quite portable),
but are built solidly enough to take the bumps and bruises encountered when hiking the landscape.
This combo covers a wide focal length range.
The 17-40 (or 10-22) and 70-200 are good two-lens combinations if image stabilization is not wanted/required.
All listed lenses are about best-in-their-class for optic quality.
While they are not as affordable as the other recommended lenses, the
Canon EF 24-105mm f/4.0 L IS USM Lens,
Canon EF-S 17-55mm f/2.8 IS USM Lens and
Canon EF 70-200mm f/4.0 L IS USM Lens
have image stabilization in their feature list.
Unless your landscape subjects are moving (wind can cause this), image stabilization can make the difference between getting the shot
and getting a blurry picture in those times a tripod is not available or wanted.
I threw one prime lens into the list -
the Canon EF 24mm f/1.4 L II USM Lens.
This focal length is very commonly used for landscape photography - and it delivers superb image quality right into the corners - even at wider aperture settings.
Thus, it can be a good choice for capturing your landscapes.
Read the full reviews to see which lens(es) are best for you.