Using Rock as Mulch and Soil Amendment?

[Geila]

Hello fellow gardeners,
I just read a book on Mediterranean gardening and the author raves about using rocks and gravel to amend heavy clay soil for better drainage and as a water-conserving mulch.

Has anyone tried this?

I live in a dry climate and this year we are really dry and already breaking heat records. Plus, water prices keep going up every year! We've packed our little city lot with tons of trees and plants to create lush gardens and I'd like to reduce the water usage. Our soil is heavy clay and hard to work with too.

But the cost of that much rock would be substantial and I'd really like to hear some success (or failure) stories before I invest the labor and money.

I'm picturing something like this*:
http://img4-1.sunset.timeinc.net/i/2009/07/altered-path-l.jpg?400:400

http://img4-3.sunset.timeinc.net/i/2009/06/water-shrink-lawn-l.jpg?400:400

*photos courtesy of Sunset magazine

[iris lilies]

I guess that pea gravel and tiny rock are ok if you are using them in an area where you never have to mow with a machine.

Personally, I use all wood mulch chips provided free from the city, I would not buy mulch. I hate rock, actually, Wood mulch decomposes and feeds your soil.

[Birdie]

I work in a one acre demonstration garden and we have the entire place mulched with wood chips instead of rock. We do have a cement walkway through part of the water efficient landscape garden, but all of rest of the planted areas are mulched with wood chips. We call arborists and ask for their wood chips if they have a tree job in the area near our Horticulture center. If they have them, they drop them for free. It tends to be a big load, 10 or 14 yards or more. You might check with some tree companies near you and see if that is a possibility.

[iris lilies]

I work in a one acre demonstration garden and we have the entire place mulched with wood chips instead of rock. We do have a cement walkway through part of the water efficient landscape garden, but all of rest of the planted areas are mulched with wood chips. We call arborists and ask for their wood chips if they have a tree job in the area near our Horticulture center. If they have them, they drop them for free. It tends to be a big load, 10 or 14 yards or more. You might check with some tree companies near you and see if that is a possibility.
yes, here tree companies have to pay to dump their wood chips. If you can get their ground up wood, that is a win/win, it keeps it out of the landfill. Now, the chips may not be perfectly formed things that you would get if you buy them, but I would say: do not be picky. Just take the free mulch.

That said, I will NEVER forget the perfect batch of mulch from the tree company DH worked for. It was hardwood oak cut into perfect squares. It lasted two years taking more than one season to break down. God I loved that stuff and I feel as though I can die happy becaus eI have had The Perfect Mulch.

[Birdie]

That mulch sounds wonderful.

Some of the stuff we get has small logs and branches in it; sometimes a little garbage. As we fill wheelbarrows, we just pull that stuff aside. I take the small logs home for my outdoor fireplace. But, we use a lot of mulch every year so we need free.

[Lainey]

I had a landscape guy tell me once that the wood chips attract roaches. Well, that's all he had to say and so although I like the look of it I never used it. But is it really true?

[puglogic]

I had a landscape guy tell me once that the wood chips attract roaches. Well, that's all he had to say and so although I like the look of it I never used it. But is it really true?

No.

All mulches, if they provide a nice cool damp environment, will attract some kinds of insect life as shelter. I've never seen roaches in any of mine, gardening in 5 wildly different states, though I do see pillbugs occasionally, or a millipede, or something else that's supposed to be there. It's nature. It's what things do. This is why I distrust most "landscape guys" -- they are often fairly ignorant and often know little more than the right poison to put down in the right place, and how to separate you from your money the fastest.

[RosieTR]

I recall roaches in our yard in Phx. It could have been the compost bin was the source but I can't remember. Perhaps you can ask at the Permaculture booth at the downtown farmer's market? We seemed to have problems with all kinds of bugs, and I found roaches to be way less of a problem than the ants, which bit.
Watergoddess: Wood mulch will break down into beautiful soil and very much help loosen clay. I don't think rock does anything to loosen soil. Also, rock is hot so you have to consider that. A very good compost tilled into the soil will help, as will certain plants (specific to your area). Ask several nurseies in your area as well as finding the county extension website. Chances are if you're in a hot dry climate they will have info on using plants to help decrease water use. Almost anything is better than turf grass, but it's important to get stuff that works in your climate and know how it works in your climate.

[SteveinMN]

Every time we plant annuals at the front of the house, I curse the previous owners who used a rock mulch on the area -- and then (the same owners?) covered that up with landscape fabric and then put down more rock mulch (not even the same color). Rock is almost forever. It will break down far slower than any wood-based mulch I can think of and I just don't find it pleasant to work with. Over the years, we've slowly excised the topmost rocks from this bed, but I would never ever mulch with rocks. JMHO.

[pinkytoe]

We use a lot of crushed or decomposed granite - looks much like very coarse sand. Great for pathways or mixed in with soil to improve drainage.

[Geila]

Thanks for the feedback everyone. I'm glad at least one person has used rock! I was starting to think my idea was crazy.

I guess the suitability of rock depends on what kind of gardening you do too. We rarely plant annuals in the ground. Our plantings are all perennials, shrubs and trees. I use annuals in pots for shots of color but not that often. We're also lazy; we never feed, fertilize, compost, anything. We plant, water and leave it. So the idea of mulching once and forgetting about it is very appealing.

We've been using wood chip mulch for years and I haven't seen any bugs, but I also haven't seen any improvement in the soil. Granted, we only top dress when it gets bare - definitely not every year. I got a private message with excellent advice on improving clay soil and I'm going to think about that. I also might try the rock on a small area that currently gets too dry and see how that goes.

I did find in my research that rock provides the least amount of water evaporation of any mulch. Probably why desert gardeners use it. And honestly, California is starting to feel like a desert. We are so dry right now. And windy.

Thanks again everyone. I'm going to keep thinking about it.