Shiva wrote:

No matter how thick the pine bark, leaves, or straw, I still have lots
of weeds.

Don't we all. What kinds, annual or perennial? Do you overhead water?
That's one weed culprit. For annual weeds, it's pretty simple. You have
to weed to scrape the ground to kill existing weeds. Then you mulch.
Then you only water the good plants, not the whole area. As weeds come
up one at a time, your remove them, roots and all and never, ever let
the seed heads ripen. Existing weed seeds can't germinate because they
aren't exposed to light. New weed seeds germinate in the mulch and pull
out easily. If you can't get them early, they'll establish by extending
roots past the mulch into soil. Annual weeds can produce 100,000's of
seeds in a single season, so the seed heads are the key. Most will
ripen after they are cut, so removal of seed heads is the key. Paid
gardeners ignore that fact. It's called job security.

Weeds that propagate from roots (like bind weed) are a pita. They
deserve handpainting with Roundup.

As for the voles....I wonder if the mulch is the problem or if the
voles are the problem. I have some kind of burrowing rodent. The rodent
doesn't see to kill the roses, but it does divert precious irrigation
water down its burrows, as in glug, glug and then a gusher 25 feet
away. The mulch simply hides the openings to the burrows, disguising
the problem -- which is the rodent. I'm looking for a solution that
stops the rodent underground freeway with cages.