My county gives away free mulch. People bring in downed trees,
branches, etc. to the county dump, where it is ground up and put in
huge piles. Up here in Appalacia, there's lots of downed wood.

Thus, we have an essentially limitless source of free mulch. The mulch
isn't all that pretty, and is probably considered low quality; it is
mostly ground hardwood with a sizeable minority of pine and a
sprinkling of random woody brush.

The other day I was down there shoveling the stuff into the back of my
pickup (the county has a frontloader that provides a filling service on
an irregular basis, but I always seem to miss it), and the caretaker
came running out of his shady spot yelling at me to stop.

He said that I was taking the mulch from the wrong pile -- that the
stuff I was loading had just been ground that day and would kill my
plants, particularly if there was a lot of pine in it. He said that
mulch had to sit for a couple of weeks and ferment a little before it
could safely be used. He strongly suggested that if I was using the
mulch for flower garden that I use the next pile over, which had been
sitting for a couple of weeks. He said that the pile I was digging
from would be good for driveways and walkways, but that I should
be careful about using it around plants.

I had never heard of that. Is that so? Does mulch have to "age?"

billo