I am looking to do some landscaping around our house, and plan to put down a 2-4 inch layer of rock around the foundation of the house, between 2 and 6 feet out, depending on the area. I've dug out the area a few inches down, and now I'm ready to put a weed barrier in. I have heard good things about Dewitt products, and when browsing their website, they sell both "Landscape Fabric" and "Ground Cover". What is the difference between these two? From what I can tell, the "ground cover" also has UV protection, which I don't need since it will be underneath rock. There will be plants intermittently placed throughout the rock, so I'll be making holes in the weed barrier for these to grow.
I fully agree with stormy about the use of landscape fabrics but I have an alternate suggestion. At the end of my answer, I'll address whether to use landscape fabric or ground cover.
You say you'd like to place a border of rocks 2 - 6 feet from the bottom side of your house. If the ground was leveled properly around your house, it will slope gently away from the walls. This is to prevent water from heavy rain (even with roof overhang and eavestroughing) collecting against your house leading to damage.
So go for a 2 foot border of rocks only - no wider. Then using landscape fabric makes sense. Dig out the border a few inches deeper and put down sand in those few inches, then place landscape fabric on top with 3 or 4 inches of rock on top. You'd be surprised at how much rocks will settle lower in time. Subtle ground movement you wouldn't notice will nestle the rocks tighter together. You don't want to keep adding more rocks through the years. When you lay the fabric down, make sure it's wide enough to bring the edge up to meet the soil level (like the sides of a pan) to prevent soil drifting into the rock border.
Please don't attempt to put a wide border of rocks around your house with landscape fabric and then put foundation plantings in it. It'll only cause headaches for you in the future. Even if you did, as the foundation plants grew, they'd end up covering much of the rocks so it wouldn't be noticed. Save money by placing a narrow unplanted 2 feet border of rocks only.
I'm assuming you want your efforts to last many years. Use the UV protection ground cover instead. It's a little more costly than landscape fabric but having a border only 2 feet wide than 6 feet will save money. Depending on how much sun and the strength of the sun where you live (as the amount of UV isn't even all over), some UV will probably make it through to the fabric - more by the edge near the border of soil.
This last suggestion is my opinion only so talk it over with someone how knows the product well if you think it unnecessary. I've got a lazy streak in me and if I put all this work into the project, I sure wouldn't want to re-do it, even if it was 5 or 10 years later! I'd want it to last as long as possible.
Well, you may not like my answer but this is one of my major pet peeves. This fabric was never meant to be a weed barrier. It will not stop weeds. Installing this fabric is for one reason only and that is to stop what we call 'sumping'. Not in the dictionary, I've looked, it is what we call it in the landscape construction field.
What this fabric was created to do is to provide a membrane between the soil and rock/gravel. Pressure from above such as walking or driving on your rock and even the weight of the rock itself without a membrane will cause the 'fines' or soil to come up and fill the large pore spaces. Your rock and gravel will eventually disappear down into the ground and you'll have to replace your rock or gravel every other year.
Weeds will grow in mulch, rock, gravel just fine. Seeds blow in or get pooped out by birds and they will grow. 2" of mulch or gravel will block out the light and the weed seeds in the soil will not be able to germinate. That fabric does nothing for weed prevention. It does however protect your investment in rock.
Used in plant beds beneath mulch infuriates me. Why? Because I had to spend time with new clients to explain why I wouldn't take them on as clients if they didn't pay me to take that stuff out of the plant beds. It was tough work (for my guys as well) and a big bill, but amazingly I never lost one of those clients. Mulch is weed control and fabric is just worthless.
The worst part is that fabric stops the entire cycle of 'feeding' the soil organisms. Soil organisms, both micro and macro are only able to get their energy from decomposed organic matter. Plants need these soil organisms for many reasons; tilth of soil that allows air pockets and great drainage, chemicals (fertilizers added later) to be incorporated by the soil, these organisms are essential for uptake of these chemicals and the improvement of soil over time. Soil organisms come up to the surface if there is decomposed organic matter, eat and then go back into the soil profile to poop it out, mixing these organics into the soil for you.
My favorite mulch, where I used to live and work, was called Gro-Co. Human poo and sawdust completely decomposed so it was no longer the same ingredients even chemically. Sadly, I have found this is not available everywhere. Smells wonderful, looks gorgeous (dark taupe, extremely fine, no lumps, no sticks, no rocks, no weed seed and no pesticide residues) and has nitrogen incorporated. A bit high on the heavy metals so it isn't to be used in vegetable gardens. However, our tap water shows higher levels...
2" of this every other year is the best weed barrier in the world! You have to replace it because those soil organisms are loving this stuff. It is already decomposed! They are mixing it into your soil for you. It is the best thing for smothering weed seeds. I used to just dump it on lawn areas I wanted to make into plant beds. The next year, decomposed grass and no weed seeds. And it is gorgeous (I am a Landscape Architect which means I am trained to know what is gorgeous and what is not, like artists and composition). And it smells just yummy, I kid you not.
If I were you I'd call your water/sewer utility people to see if they make this stuff where you live. It won't be called 'Gro-Co' as that is the name Sawdust Supply used in the Seattle area. The bagged stuff I've found is not thoroughly decomposed and stinks. The federal government is involved with the companies who want to make this product. They test this product 5 times before being allowed to the public. I have to say this again, my guys were blown away at their next visit a week later at the difference in the health and beauty of the plants at the site we had just installed this stuff. The clients were mine forever.
If you are not able to find this product in your city use the finest ground pine bark available. Don't waste your money on cedar. Takes too long to decompose to be available to the soil organisms. Sprinkle alfalfa pellets (used to be kitty litter but now I've found Rabbit Food is the same) on top of the new finely ground bark. This is nitrogen and the first thing that happens with anything newly dead is it has to be decomposed. Decomposers have to have nitrogen to do their work. They will use the nitrogen in your soil and make it unavailable to your plants to do their work. Adding a bit more right in the bark will greatly enhance, speed up decomposition without taking away chemicals your plants have to have. The other soil organisms go dormant or die until there is 'food' to be had. Once the decomposers have started their work and there is decomposed organic matter to feed the other soil organisms, they wake up and their eggs hatch and you've got a live, healthy soil again.
I am glad that you asked before purchasing this 'weed fabric'! Some marketing genius thought to 'add' that to sell more fabric but totally a lie. And detrimental to boot.