Posted: 25/05/2015 at 10:20
I have used a membrane covered with bark chippings in a shrub bed successfully. Shrubs stay where they are put. I cut crosses in it for planting holes.
But some years ago I tried with perennials, I would not advise it. Clumps of perennials increase in size and when they can't then some of them spread their roots sideways and pop up in the planting holes of others. The membrane makes it very difficult to work with. Bark or a good mulch is much easier to cope with, but you will always have to do a certain amount of weeding in a bed of perennials.