Since I'm not that long into 6x6 I'm still searching for a good mis-en-scene for landscapes. Street shots and people seem to benefit more from the format.
One thing I already discovered is that I won't be using 6x6 that much for landscapes because of composition reasons.
When prominent trees are involved, things quickly become easier.
I'd rather swith to 9x6 for landscapes. It tends to be more natural. Did you ever see a perfect square in nature? Nor did I.
9x6 lies so close to the golden cut (errrrrrrrr... is this the correct name for the almost 2/3?, I translated it rather litterally) which tends to support landscapes.
It might be a challenge to capture landscapes in a square, free from all said rules.