I'm using mazus reptans/Mazus among my stepping stones. It spreads quickly and will take some sun but I don't know how invasive it might be as this is only my second year with it. I don't know how easy it will be to keep to a specfic area. It has a little bloom that looks like a tiny orchid and this spring, the plants between the stones was covered in the little blooms. Last summer, after planting it, it bloomed some but nothing like the spring show this year. It is easy to propagate by cuttings.

Here is what it looks like; it is the smaller ground cover in lower right hand corner. This small patch was started last summer from a few cuttings so you can see how quickly it grows.

Mary

I have mazus around a stepping stone path too. I have had it for about five years now. It is wonderful. It's evergreen, and stays very low, especially after blooming. It makes a very tight mat that keeps 99 percent of the weeds out.

It will take some sun as long as it never ever dries out. If it gets dry, it will go dormant or die. My well established areas seem to go dormant until the weather cools and the rain returns.

Once each year, I have to take my clippers and cut it away from the stones. When it has its big growth spurt in the spring it will spread right across the pavers. One trim a year takes care of it.

Since I don't want it in my planting beds, I also trim it back from them each year (but only once is needed). I keep thinking I will put in some edging to stop it....