What does "natural" mean to you?

Gravel is from a natural source, riverbeds, and shorelines can have gravel, but gravel outside of nature is more commonly found as a paving material for a driveway or road.

It sounds like you are going to be using gravel/stone as a mulch and are looking for suggestions about how to create a shape and an edge to the mulch limits. ...?...almost as if you're painting a picture on paper and want to know where the paint will go...? It'd be a lot easier to describe a solution if we could see a picture. (upload a pic to your photo-hosting account, get its html code (there) and paste it here while writing your message.)

Be forewarned, gravel mulch is not going to put a permanent stop to your weed situation. It will work for a while, but eventually, enough dirt will accumulate above the fabric to support weed growth. Once in a while I see it and think it looks OK in a particular situation, but in my mind it has too many disadvantages. The main problem with it is when you later decide to make a change and now the gravel is in your way and you don't want it mixed in with the planting soil. It can be a big mess trying to work with it...or remove it. If it was some kind of wood product it wouldn't be much of a big deal if some gets mixed in the soil. The other main problem is that it doesn't really stop weeds long term.

Maybe it's beyond a simple transition from plants to gravel mulch, but the real transition is in perception of how all the bits and peices fit together to make a whole picture?

The first image is the aerial parcel map where my lot is located and its direction. Notice that the orange-red lines indicate the lot border.

The second image is what I would like my Xeriscape to be resemble to in a simpler version without the various terrains that lead to the woods.

I have not figured the entire plan for the landscape/xeriscape yet, but only got a rough idea what I want to do: no lawn, planting drought-tolerant plants in flower beds, gravel covering the rest area. I am TRYING to make everything as sustainable/eco-friendly as possible, while not having much budget to do any intricate design or heavy labor. Any suggestions will be much appreciated.

The first image is the aerial parcel map where my lot is located and its direction. Notice that the orange-red lines indicate the lot border.
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The second image is what I would like my Xeriscape to be resemble to in a simpler version without the various terrains that lead to the woods.
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I have not figured the entire plan for the landscape/xeriscape yet, but only got a rough idea what I want to do: no lawn, planting drought-tolerant plants in flower beds, gravel covering the rest area. I am TRYING to make everything as sustainable/eco-friendly as possible, while not having much budget to do any intricate design or heavy labor. Any suggestions will be much appreciated.
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Wow...what a difference a picture makes. This isn't the problem I envisioned at all. It looks like you're trying to create a simulation of a body of water using gravel. The illustration you show is Japanese inspired...a small pond, an island, a bridge, and stepping stones...surrounded by plants and some small "boulders"... miniaturizing Nature, as it were. At first glance it looks like the "pond" edge is rather busy, but in shape (as viewed from above, it's not that complex. The "boulders" and plants at it's edge make it appear more complicated because they fragment the edge and give it a crenelated appearance.

I think one key to creating this simulation of water is honoring the law that says water never runs uphill. Notice that the "pond" is perfectly flat and when the terrain begins to climb, the water stops. The up-sloping ground becomes the bank of the pond. Sometimes it's covered with groundcover. Sometimes it's punctuated with a plant or boulder. (In my mind the picture would look better and stronger if it were simpler. To me, a quick glance makes it look almost as if there's a lot of junk sitting around the yard. Fewer, but larger boulders would look better.)

For some inspiration search Google images for "zen garden." You'll see this gravel-as-water theme in umpteen variations. Then, if you'd like more input, I'd post a picture of your actual yard...so that people could see grade & whatever else there is.

For myself, I think this is a good way to use "gravel" in a yard...far superior than as mulch in between plants (as I first thought.)

Yardadviser, thanks so much for your response. According to your initial response, you said that gravel wouldn't permanently stop weeds. I am concerned about that! I have fought with weeds for so long, and I am REALLY tired of pulling weeds.... At my current yard, I installed landscape fabric and then river rocks, actually very similar to my initial post. I originally sowed wildflower seeds and amended better soil on the hillside, but the seeds and soil amendments ran down to the river rocks. Thus, I can much related to what you meant by gravel not permanently stop weeds. However, I just LOVE stones, rocks, and pebbles so much that I want to try it again. Only this time would I do it right!

Yes, I would LOVE to have more input, because this flat land really got me. Thanks

If you ever figure out 'right', let the rest of the world know. It seems the best way of controlling weeds in gravel is to live in a part of the world that is dry enough that few plants will grow as weeds in unirrigated places. Here, it's a constant battle to keep weed trees out of gravel driveways where you would think they would get the idea that cars don't want them there. Gravel paths are a lost cause, and ornamental gravel is just a non-starter.

I wouldn't even want to be in charge of weeding all that groundcover.

To be sure, weeds have the upper hand. In the battle they don't have to take time off to go to work or maintain family life. They devote 24 hours a day to perpetuating themselves. Any bare ground, in most places, will be overrun with weeds in a relatively short time. This being the case, I can tell you that it leads me to choose chemical control as my preferred solution...because it's the quickest and easiest. In my vegetable/flower garden where it's easier to control weeds, I do it manually, but in the landscape, it's too time consuming and difficult. I use Glysophate (Round-up is one brand) usually in combination with a 2,4-d-based herbicides. Glysophate alone is ineffective against many weeds. I also use a back-pack sprayer. Carry sprayers make it ten time harder and they'll pull your arm off before you get done with the job.

The thing to remember about weeds is that it's a bitter fight and if you can't commit to the end, they'll win. With a good layer of mulch as one component of your arsenal, it usually takes about two years after a bad infestation to get to a state of relative victory. A bad infestation means that there are tons of seeds lying in wait. And they have the ability to stagger their birth in order to wear you out. They keep coming and coming. There's also pre-emergent herbicide, like "Preen". It's a granule sprinkled on the ground (great for mulch areas) that attacks newly sprouted seedlings. That would probably be helpful, too. Each type of herbicide plays its part. Also, woody or perennial roots require digging out or repeat treatments of herbicide before they finally give up. The good news is that poison ivy is one of the easier weeds to get rid of!

After weeds have been controlled for about two years and mulch is maintained, it requires very little herbicide to keep things in balance. Actually, then, a person could even keep some (or maybe all) weeds maintained pretty easily by mechanical methods, so that becomes an option.

Weed control is a huge subject and there are myriad details not touched on here. And I'm far from being an expert. I'd be as interested as anyone in hearing about great ways to conquer weeds.

Here on the west coast we tend to use a lot of gravel and gravel like materials as our main ground/ suface covering.
We have the benefit of no over head rain for at least 6 months so that makes weeding a bit less daunting than a climate with a rainy active growing season.

Our winters are beautifully mild and rainy , which can lead to a lot of weed growth in a gravel groundcover area if there is not an astute amount attention paid to preparation.

In my back yard garden the main walking and seating surface is gravel. I have very little weed growth thus weeding maintenance ( maybe 5 minutes a month )
I used a double bonded weed barrier cloth in my sub base. On top of the heavy duty felt weed cloth we installed 2 inches of class II fine ( quarter inch minus ) aggregate. It was heavily compacted to an asphalt like texture. Then the loose quarter inch chipped aggregate with granite fines mixed in was top dressed.

This is the basic recipe with the main ingredient being a well compacted class II aggregate sub base.

below is a picture of the main gravel path thru my garden :

The border edging is a composite lumber - common trade names are Trex or Epic. I plant up to the edge so that it is eventually obscured by the foliage. {{gwi:47661}}From Pina Colada May 15

This garden was designed by Topher Delaney in San Francisco. (photo below)
compacted sub base, weed barrier cloth, gravel top dressing
{{gwi:47662}}From AIA garden tour 2009

I did not see the actual installation but it is rather standard professional installation practice here that a stable sub base of class II is installed ontop of a double bonded weed barrier fabric - after which you top dress with either gravel, crushed glass, mulch, tumbled ceramics or tumbled stone.

Below is a garden designed by Shirley Watts. She used crushed and tumbled ceramic shards as a mulch. ( compacted sub base, weed barrier cloth , tumbled ceramic top dressing )
{{gwi:47663}}From AIA garden tour 2009
{{gwi:47664}}From AIA garden tour 2009

This garden designed by Alida Blair was built ontop of a decomposed granite hillside so the sub base was the hill itself - no requiring any compacted class II.
{{gwi:47665}}From Alida Blair Landscape Design

So in my experience, it is all about the sub base preparation in getting a good start in keeping the weed growth in check.
Prepare a dense but permeable sub base on top of a heavy duty weed barrier and then top dress with your choice of gravel, stone, ceramic, glass or organic wood mulch.

D-D, is vibratory plate what you use to compact sub-base in prep. for aggregate ...or other method?

yes, we use a viber plate to compact our sub base. Also use it to compact interlocking cobbles ( we put a scrap of carpet on top of the cobbles then run the plate over them )
On larger project a steel drum roller is used. ( but we usually don't work on jobs that big )
the viber plate is the yellow lawn mower looking machine in the photo below:
{{gwi:47666}}From Before and After Projects

Oh, wow. I learn things everyday!! Thank you DD. You have provided great info. After reading your post about compact sub-base, I searched more info about it. Not only is it crucial for the exposed gravel walkway/backyard area, but also for the paving areas. I read info about different types of sub-base materials, such as type I and Type II. You basically use Type II, so.......What can be used for compact sub-base type II aggregates? Is there a specific name for it (the article I read about only mentions about its size being smaller than type I), or the materials do not matter much, as long as the size of it is small? Do you think I can use Recycled Asphalt Products?

d-d - I just wanted to say... I love that shot of your garden and path! I don't have a clue what most (all ?!) of those plants are, but that's the look and feel of a garden/path that appeals most to me.

chueh, I re-read your initial post and see that I'd forgotten about one of your main issues (now that I understand it): how to create an edge of the gravel "pond" when your lot is flat, i.e., no topography to give you a natural "bank" at the "water's" edge. You can create some topography. For one thing, if you will be installing stone mulch that is a few inches thick, you will be needing to excavate to have a place to put it so it doesn't look like "water" sitting elevated on top of the ground. That excavation is good berm-making material. Your berms do not have to be high. They can be subtle. Also, you'll be planting groundcovers or shrub masses and you can combine them in ways so they emphasize the height of the berms. Some big boulders, alone or backed with plants could fit in. Even a hedge, natural or sheared could be an object that edges the "pond". Some mowed lawn could work if it were retained with steel or aluminum edging. If an existing (or proposed) wall is part of the scheme, it could be sufficient as an edge. When you finish, I hope you post some pictures!

Also, look into crushed brick as a possible material. In general, it looks great (not sure it would go with the palette you want, though) and is an excellent walking or driving surface. Search Google images for it to see some samples.

You got it, yardviser. Wonderful wonderful advice. Thank you