How mulch mulch is too much?
I am expanding my perennial beds and ordered leaf mulch from my county. My math skills were apparently lacking, so I ended up with a lot of mulch! Some resources say to not pile mulch too thickly, so I wanted to poll opinion here.
1) Where I placed the leaf mulch in existing flower beds, I left several inches clear around my plants. How many inches of clearance is recommended?
2) When I ran out of places to put the mulch, I created new beds by first laying down cardboard/paper and then piling the leaf mulch thickly on top. (In some places I ran out of cardboard and just used mulch). This is mostly about 3 inches, but in some places I've got it piled higher. Is there any potential negative effect of this?
I figure I'll add any remaining leaf mulch to my compost pile (I have few trees, so I have a limited amount of leaves for my pile).
Any comments or suggestions?