I'd recommend not using landscape fabric at all. If the issue is keeping plants/soil anchored, using strategically placed stones/pebbles to prevent soil and plants from washing away is a better idea.

Landscape fabric will inhibit spreading/reseeding of desirable plants It also tends to cause compaction of soil underneath it which interferes with oxygenation and water absorption. Soil and debris builds up on the fabric so weeds sprout and root into it, creating a mess. The fabric also degrades over time.

Here is a link that might be useful: Planitng a wall

Hence why I am asking how big of a hole is needed so that it will not inhibit the spreading.

Also, strategically placing rocks will not stop them from sinking into the clay based soil over time.

I would imagine it would depend on the size of the perennial you are planting. having said that, I agree with Eric.

i wouldnt use it either ...

i dont understand how the first person says that.. and your response is.. that is why i am asking how big a hole ...

dont use it...

almost all weed seed is airborne.. and one minute after you lay it down .. and cover it with rock.. seed will settle on top .. and you will NOT be able to pull them out.. and it will interfere with air and water movement into and out of the soil ... its just bad all around ... and not really designed for soil retention on a hill ...

if you insist.. the answer is ... 7

ken

From the voice of experience, DON"T use it!!! I had to learn the hard way, and ripping out the landscape fabric later is NOT fun. As stated above, the weeds still grew above the cloth, so there was no advantage to using it.

Heed the advice of those who've used & regretted using landscape fabric to suppress weeds. It doesn't. I haven't used it myself for the very reasons cited above altho' my less fortunate neighbors are regretting their mistakes as I write this.

I don't mulch the steep slope in my garden--periwinkle grows on it and keeps 90% of the weeds under control. I've had success in my garden beds using shredded bark mulch on top of recycled corrugated cardboard.

Acdacd, you probably expected some helpful answers like five inches, etc.....but as you can see there are strong feelings about landscape fabric. And that is because many of us have gone down that path already and don't want others to make the same mistake and then be disappointed, discouraged and disgusted.

You might be better off mulching very heavily in the areas where there are no plants in order to keep weeds down. Other than that, plant closely together so the weeds can't get a foothold. I used yards and yards of mulch on my large slope for a few years, but now that everything has grown in we never mulch at all. A couple times through doing a quick weeding over the course of the season is all that's required now.

I am not sure why everyone is under the assumption that I am using this as weed control-- I am not. I need erosion control for steep slope/rock wall as well as a barrier that will not allow the rocks not to sink. Also, I am not using mulch. Thanks for your opinions, however they fail to answer my question.

Despite the fact that you are not happy with the previous answers, I'll add my opinion:

I still feel like cursing the person who installed the landscaping fabric at my house - and it's been 6 years since I moved in and ripped it out, after much pain and angst.

That stuff shouldn't even be legal.

If you want it purely for erosion control there are other products specifically for that purpose which would do it much better than landscape fabric. Several companies make biodegradable erosion control fabrics which last long enough for plants to take over the job of stabilising a slope.

A picture of the area you are talking about would help people give you other ideas. As for the size of hole for planting perennials - it's just an impossible question to answer without knowing your climate, growing conditions, which perennials or your style of gardening (ie series of coloured blobs or exuberant tapestry.) And can you elucidate on why cutting an X is meant to be a bad idea?

Here is a link that might be useful: An example

And yet another gardener advising you to remove the landscaping fabric before it becomes YOUR nightmare.

Wow, tough crowd.
If you have clumping perennials, the holes should be four or five inches wider to let them expand a bit. If they are spreading perennials chose something else since they will naturally grow into the gravel and landscape cloth and cause the problems already mentioned by others.
I would only use landscape cloth for a scenario such as you're using it for- to keep gravel from sinking into the soil, usually under a gravel walk or patio. Use a good woven cloth and not anything plasticy, it will be easier to rip up if you end up redoing the bed.
As far as gravel around the plants and it holding them back, it won't hold anything back, in fact a gravel walk makes a great seed bed.... Ask anyone who has to weed one!

Acdacd, I understand your request .... you hope to create erosion control and a means of preventing small rocks from sinking into the soil on your steep rock wall slope. Floral is right... a photo would help us to see this area and your problem. Could you provide a few that show this wall?

Your concerns brought to mind what my DH and I had done many years ago.. when we were less experienced gardeners and had much more money. We wanted to redo the back area that abuts the river. We hired a landscaper who came up with a plan.

He built a side retaining wall, the top of it shows next to the tree in the last photo... put down tons of sand for drainage... then landscape fabric... then large pieces of slate and boulders for seats.. finally small stones between them with larger gravel where the land sloped down to the river.

This looked good for about two seasons. Then Mother Nature had her way with us. Dirt formed between the stones. All manner of plant life found a home. Their roots spread along and into the fabric. At first this was a tiresome, but possible, clean-up job each spring. However, in a few years it became a nightmare. The smaller rocks had become embedded in the roots and soil.

I'm enclosing some photos I took this morning. Granted, our area is probably nothing like yours. But these pictures will... I hope... show you how foolish we were to have used landscape fabric.

Embarrassing Photo #1 ... showing the patio's relationship to river

{{gwi:224760}}

Over time, dirt formed on top. Weeds thrived. Pulling them out is so hard ... their roots are trapped in sand, stone, and fabric. Spraying is not an ecologically sound option.

{{gwi:224762}}

The worst photo... shows what's happened to the bank where there once was a dock and railroad ties, used as a wall retaining wall.

{{gwi:224764}}

As you look at these photos, please realize that we planted nothing here. All of these plants have arrived via the wind, the birds, and Mother Nature's other techniques.

By the way... would any of you other fellow perennials lovers like to join us in early June for a Weed-Pulling Party? We'll supply the burgers and beer!

Molie

A 36''x36'' hole ought to be sufficient.

There are a variety of netting products sold for soil erosion control, made from jute as well as non biodegradable products.

I'd look for the biodegradable kind with wide enough spaces to allow plants to spread and for water and air to circulate properly.

I think acdacd is under the impression that landscape fabric is a permanent solution, when in fact it (and probably every other "non-biodegradable" fabric or netting) will deteriorate over time. If rocks eventually sink into the soil, some may have to be removed/replaced - there's no permanent fix. If that sounds like a chore, consider the labor involved in removing dead/non-thriving plants whose roots have grown into landscape fabric (not to mention weeds that have done the same).

It took me at least six years to dig out the last of the rotting landscape fabric and plastic that the previous homeowner installed in one growing area. At least she didn't fill the bed with lava rock "mulch".

This post was edited by eric_oh on Sun, May 18, 14 at 10:22

I second what dirt says. It is a MAJOR headache trying to remove it later. Don't do it!

Nope - not all non-biodegradable things rot over time!!!! Even if it does, you will be forever pulling out bits and pieces. Listen to the many voices of experience here - or don't.

Gravel mulch does make a great seedbed. I have a walkway that was laid out with landscape cloth with about 4" of gravel on top, the kind thats finely crushed stone that sort of interlocks after time. Actually, with gravel that deep, the cloth is no problem and weeds are fairly easy to pull out, I keep it weeded regularly so none get a foothold, it was cheaper than paving so in a situation like this, the cloth is OK.

I would not use landscape cloth in the situation described above myself. mjc molic----Its too bad, looking at that one you did above. I have seen people lay out pavers in a large area out like this with plants purposely planted among them to help hold the soil & naturalize it, the result is quite nice, rather 'Mediterranean' and natural in the finished look. The cloth would make that nearly impossible & weeding would be a nightmare. I have a few things I wish I could go back in time on too.

I think in a universally agreed upon product like this, people really feel a need to share their nightmare experiences & its a bit frustrating to have that kind of experience go to waste when attempting to warn someone else or send up the alarm. Later comes the temptation of saying "I told you so" when a roll of duct tape over the mouth comes in handy.

In your original post you hadn't mentioned the purpose for the landscape fabric.......weed or erosion control. How steep is the slope? Is there a reason you are averse to using a heavy layer of mulch? My first reason for mulching my slope when the plants went in was for erosion control, with an added bonus of weed control. If you use a decent mulch it might even help amend the clay soil a bit as it breaks down.

What was the plan for weed control on your slope?

Although it is a lot of work, and one must be careful to do it right, terracing can reduce erosion issues. Don't know if the OP would consider that an option.

Interesting idea.color>

I had landscape fabric under my front landscaping for 28 years with no issues, and no weed problem. It had "rock bark " whatever that somewhat bark-colored light weight rock is over it. It was a good quality (very heavy) fabric. Shrubs grew fine.

I'd have it done again even though when I redid the front I had to rip parts of it out where I wanted to plant. (Wanted to plant rows of hostas, hydrangeas, etc. in front of the evergreen shrubs.) Ripping it out wasn't fun, but it was simple compared with 28 years of replacing mulch and weeding.

I'm not talking about the aesthetics of stone...simply that in some cases, a well-installed landscape fabric/stone combo works great for weed suppression.