Mulch is such a versatile tool in a healthy permaculture system I could go on for 50 pages about it, but here are some links to reference later if you’re new to mulch:
why mulch? | making leaf mulch | what else can I use for mulch?
My first year of gardening, when I built the first pallet beds in 2014, my novice brain thought it was smart to buy good mulch so I purchased $600 worth (yes, it makes me cry to think of it now) of “gorilla hair” fancy cedar mulch. That $600 of mulch barely covered just the front garden and not a square foot more of my 1/2 acre plot. Having run out of home-maintenance money for the entire season on that one load of mulch I started searching for alternatives. I noticed a noisy truck down the street that was grinding up a 60’+ tree that was being removed. I jogged over and started asking questions. 30 minutes later I had an agreement with the truck operator to deliver the entire truckload of mulch in my driveway for free (this was more mulch than I got for $600 and I had to haul that myself!). I was flabbergasted, and gave them a $50 tip and 6-pack of beer in gratitude. This is not a rarity – you can almost always get free, high quality mulch during spring tree-cleanup season. There is even an app for that, though I haven’t yet tried it since I’ve now locked down a few reliable sources.
My most recent mulch delivery was 13 cubic yards of mulch, and I’m still working my way through it as you can see. By using the tree mulch in my yard I stopped it from adding mass to the landfill or recycle center, it’s now fertilizing my soil and retaining moisture, and I’m even putting the pile itself to use by planting some beans and squash into it just for grins to see how fertile the mulch alone is. I had some robust seedlings in the pile a couple weeks ago until the dadgum varmint squirrels munched on them.
*a note about rock mulch: I am NOT a fan of river rock mulch or ground cover. Many have tried to convince me of it’s merits but I have zero love for the stuff – even for driveways. Once you have it, you’re stuck with it. Moving it in or out is ridiculously heavy. It makes digging in an area that ever once had the stones so frustrating you’ll want to javelin-toss your shovel. It doesn’t do anything for your soil but warm it up and dry it out. And my least favorite thing about river rock mulch is that organic matter starts building up between, and on top of, the stones from day one even if you first lay down that terrible plastic ground cover (we can talk about this abomination another time). Within a couple years your stones are half buried unless you take extra care to keep all organic matter off the rocks before it can break down… you know, cause you have nothing else to do with your precious time in the garden. Hahaha, I mean… whew! I guess I feel strongly about the stuff. Your mileage may vary. *sheepishly climbing down off of soapbox*