In article f6794453-face-410b-8f36-347c8d5e5677
@n6g2000vbg.googlegroups.com, says...

The cardboard mulch idea is intereting. However, does it not create an
absolute breeding haven for slugs and snails?

Not in my (long) experience. As the cardboard and mulches break down
worm activity increases; the worms attract birds, the birds spend hours
scratching around for live food.

Janet