I am still waiting for someone to answer whether dry stack or mortared 2 1/2 foot wall better? I live in earthquake country and the wall will only be around 25 ft long and 2 1/2 foot high. Thanks for your answers.

I live where there is frost heave to worry about. After a lot of research and talking to a lot of people, we went with drystack. (2 1/2 feet high by 75 feet long.) We'd read and heard that mortar will eventually crack and look worse as the years go by. Drystack will shift somewhat, but should settle comfortably and be very solid if done properly. (solid base, drainage gravel, landscape fabric, slight batter into hillside, etc.) That's what we went with, with flat fieldstone. But I did meet some people who had used drylock cement at the backs of the stones, but left the fronts clear, so it looked drystack. A few of these people have not experienced any problems in many years, so it may be worth considering. Good drainage is key.

I made a dry stack wall three years ago. I love it. It has settled into the slope more but mine is only about 18 inches high at the highest point. I don't have to worry about gravel and pipe behind the wall to make sure it drains to ensure the wall stays put since the natural cracks are already there. I do not have to deal with frost upheaval either. I recently added a drip system and to hide the pipe I undid a portion of the wall and put it right back together. The cons so far are bugs. I just about had a heart attack when I found the biggest spider, the body alone must have been 2-3 inches long, I have ever seen take up residence.

We lived on glacial moraine for 20 years and the only way to garden was to build walls and terracing with the stone the Glaciers left behind. With proper footings and backslant it was no problem to dry stack a wall 3 feet high. The stones varied from gravel size to the size of a VW Bug. Since I was holding back the sides of a hill mortaring would have required an amazing amount of extra work to provide escape for water draining from the meadows above the walls. Hope you are enjoying your project. Sandy

Mortar, absolutely; but retain a slight slope on both sides.
And put inside cinder blocks, pouring mortar over them...