In your zone (Texas, for those who haven't checked your member page) this is a dead simple task requiring virtually no digging at all unless you need to drop the level of the pathway to be even with surrounding dirt. You don't need the fabric either; do a search of this forum for "fabric" to see all its disadvantages. You can lay your flagstones directly on the soil and plant or fill whatever you want in the cracks, or at worst put down a layer of sand under the stone. You just need to make sure each stone is fully supported with compacted soil or sand so you don't have the stones cracking. What I'm not clear about is whether you want to fit random shaped pieces of flagstone together, or whether you are using regular cut or paving stones of some uniform shape. If it is a real flagstone laying task, then you have the job of fitting the flagstone pieces together to make a nice shape, and nice joints. Depending on whether you want your path edges to be a certain shape or random, this can be tough or easy; in any event it is like doing a puzzle without using the picture on the box. We did a flagstone pathway; there is a photo of it in the thread linked below (finished product at the end of the thread). We actually laid down a bed of sand before the flagstone as we have drainage issues and that's a problem when it either turns to mud or freezes, which it does here more often perhaps than where you are. For the pattern, we mostly used the stone as is, cutting (with a chisel-thingy bought for the purpose) perhaps two or three pieces to fit. You "just" go out and flip (that's facetious, as they're heavy) the pieces around until you have combinations you like. Here is a link that might be useful: Thread with photo at end

The flagstone walk I built four years ago has many pieces that are 3"x4" or even smaller. They have not flipped or shifted at all. HOWEVER, I did use polymeric sand in between the stones, so that helps keep them in place. What are you going to use between yours, to plant the thyme in? I agree with Patty Cakes that weeds would do as well as if not better than the thyme, unless you plant a lot of thyme immediately. Even so, it could be a maintenance nightmare. How much to you like weeding?

I hope someone with more experience jumps in here and helps with some better answers but I'll try. In your zone you probably have some freeze heaving going on. When the ground freezes and thaws it moves, you need a 2-3" base of some sort, sand is the most common here, if you are near rock quarries you might use rock dust or grindings. You need to pack this in and then work your flagstones into it so they set even or level. Then you can fill in with your mulch or whatever. As for the crab grass, if you're going to have lawn right next to the flagstone you might consider trying to find a herbicide designed to kill crab grass and not your lawn, don't know if that is possible as my lawn IS crab grass with alittle bermuda. I know that digging out and adding sand and releveling is alot of work, we are currently working on laying 23 Tons of flagstone around our house. It has been going much slower than I expected but DH has promised that as soon as we finish the front yard area he won't be so picky with the rest of this project. One more thought, I went on a home and garden tour yesterday, one of the homes was owned by a landscape designer who had laid a flagstone walkway all kinda cattywhompus, uneven like, and filled in the cracks with fine gravel chips. He said it made it look old, it did at only l year, and he could spray any weeds that grew with roundup. I'm taking DH over to take a look and see if we can get some more ideas. Good luck on your project.

You have a very nice natural looking area. Below is what I did with my steps, I had to go for something sturdy instead of keeping it more natural. I'm up there at least once a week including when steps are wet or frosted and feel no danger of slipping or falling. You may not be able to tell but there is 2 6x6x24 inch landscaping timbers per step. I figured 12x24 inches is big enough for anyones foot. Look near the top you can see 2 per step. I anchored each timber with 2 foot rebar on both ends. I used 4 8-foot timbers and sealed the ends of them with marine varnish once cut in 24 inch lengths.I put myoporum along the edges as I have it elsewhere also. The block retaining walls were already there but I have raised them. There used to be just 1 railroad tie per step but they started to rot away and too much erosion. I think your aussie will just wear away the flagstone and soil and any groundcover in between.