Dry stacked walls can actually be easier to build than mortared ones. Both require some knowledge of stone masonry but mortared walls also have to deal with appropriate foundations to allow for frost heave as well as drainage considerations.

Since your wall is not that big, I suspect you could tackle a dry stacked wall yourself, especially if you could get you hands on some slate like you already have in your garden as slate tends to have nice flat surfaces which are easier for beginners to work with. As to the specific instructions, there are many good books on the subject that you can buy or borrow from your local library. The keys to remember are 1) build on a solid base (well-compacted subsoil, or packed gravel or something like that); 2) always slope the wall slightly into the earth it will be holding back (the back of each stone should be tilted downward ever so slightly, and each row should step back slightly from the one underneath it); 3) always stagger your joints (like brickwork); and 4) the pieces on the top row, called capstones, should be as large as possible so as to have fewer joints for water to seep down into the wall and because they are naturally most vulnerable to shifting since they do not have the weight of other stones on top of them.

If this seems like a lot, don't be intimidated. I built an L-shaped wall in my front yard (30' by 20' by 2' feet high at its highest point) to deal with a similar sloping issue that you have and it has come through several winters with no problems. This year I built a 50' long wall in the back yard that is 2' high for about half the length and then slopes up to about 4' and arcs around the patio, then turns a corner to finish at the lot line. I've had no training; I just read about the basics and jumped in. You'll decide early on if you have a feel for working with stone.

As for the placement of your wall, I would position it back from the sidewalk and fill in the space in between with a groundcover as you suggest. First, using natural stone you are going to have little gaps between the wall and sidewalk which will no doubt fill with weeds and it probably easier to manage a somewhat larger space with a groundcover. And second, you do not want to have your wall destroyed if the sidewalk is ever dug up to be redone. If your wall is right up against the sidewalk, I suspect it would be impossible for the city to work on it without destroying your wall.

Good luck. I'd love to hear what you decide on.

I like this idea more the more I think about it. Now you have me wanting to do the whole slope and make my own L shaped wall and flat front lawn. Shame on you! :)

Thank you much! The ol' spouse is going to freak out about this one muhahahhahahaha!

It's only a small wall, you won't even use a whole bottle of motrin.
Some simple rules- one over two and two over one.
2' high and 5' long you could just about lay a row of stone on edge with a large rock on either end.
Or you could purchase a piece of stone 2x5 and be done with it in one swell foop. Around here there are curbstones and foundation stones that large.

Hmm. I'm also considering turning the slope into wide rough stone steps. They won't necessarily go to a path but it's sort of a walking-through area, about 5'x5' and steep.

I'll have trouble ending a wall because on one end it will either have to meet a perpendicular concrete wall that slopes down to meet the sidewalk or end sort of abruptly before that spot. It's sort of tricky to describe...

We don't have alot of stone laying about here like in much of New England--it's mostly imported and the big chunks aren't as easy to get a hold of as the smaller ones, but I'm definitely getting some good ideas from y'all!

Sounds like a beautiful project! You might want to check on the property lines and buried utility locations before building by the sidewalk. Where I live, the private property begins 12 inches back from the sidewalk, and there are often water mains, etc., in that 12" that occasionally have to be dug up for repairs/imporovements.