Composted bark

I have been using composted bark on plastic membrane in my garden but this has a number of drawbacks.
One is that it gradually rots down into a dusty compost-like material. The shrubs growing there send out roots into this "compost" ABOVE the membrane instead of sending out roots much deeper down in the earth as they normally would.
They then become much less stable in high winds and also dry out much quicker in hot weather.
I am considering changing to wood chips in the same way as my local Parks Dept. has done. Has anyone any comments on the use of wood chips and have they actually tried them?

 

Hi Peter, composted bark is better used as a soil conditioner than a mulch. Much better to use chipped bark, though this will rot down too and should be topped up every year. I`m trying to work out why your shrubs are rooting above the membrane. When you did the planting did you cut a hole in the membrane or a cross? Also, you say you are using a plastic membrane, so is this a polythene sheet or proper weed control fibre? David.

 

Hi Peter we have done the middle of our side garden into a little woodland effect so to speak and have done the following;
First placed some cardboard on the soil, then weed membrane and finally bark chippings.



I have used this method many times before in our old garden and it works well and as David says you will need to top up the bark each year and although it may be not ideal to look at after a while a good rake over seems to perk it up no end.
Helen.xxx.

 

Composted bark.
Thanks for the replies from David and Helofadigger, and the excellent photo.
I should have called the sheeting "Polypropylene permeable membrane" (trade names being Terrum and Phormisol) to differentiate it from solid plastic sheet. Also, I should have called the composted bark by the proper name "bark chips". Sorry about that.
David, I normally cut a cross and carefully work the cut edges snugly round the stem. I am talking about shrubs and small trees, not herbaceous plants. One example is Hebes which do send out exploring roots ABOVE the sheeting into the fine composty-like material (a fine rooting medium!) which the chips gradually rot down to produce. This should explain my stability and drying remarks more fully. We found this out when we had to move things which were in the "wrong" place or were found to be too big/small, etc.
I have a 1/2 acre garden and I am talking of large areas put down to Terrum & Chips to save work and weeding. Seeing that our Parks Dept. had moved over to wood chips (as opposed to bark) it occurred to me that this would be better for me and I hoped someone would have used them. They don't look as "natural" as bark, being initially the yellowy colour of natural wood but seem to be far slower to rot down.
My original question still remains, are there any users of WOOD chips out there ??