I have been mulching for the past half-dozen years or
more but I still don't feel I really know what I'm doing.
The mulch I have available is chipper wood in various
stages of decay which is provided by my local town.

I am pretty sure I killed off my asparagus bed by applying
too thick of a layer of this mulch. Only later did I notice
that the mulch had formed a rather particle-board-like
dense layer a few inches down.

Yesterday I decided to pull it back away from my thornless
blackberries to see what was happening underneath, but
I could not really tell if there would have been a problem.
Some areas had indeed compacted into impenetrable material
but since the blackberry shoots are usually adjacent to
previous growth they might have easily found an exit.

Is this the situation with mulch? Every year you need to
pull it back and see what is happening underneath?