I recommend cardboard, not newspaper. Newspaper disintegrates quicker than cardboard. You need to make sure to overlap the cardboard about 8″ to 1′ to make sure there are no gaps for the weeds to find a way through to the surface and sunlight. Weed seed may also land in the mulch on top and sprout and grow…they will need to be pulled. Cardboard is a permanent solution though. Eventually even the cardboard rots away and weeds can grow and will need to be pulled. There is no permanent solution to weeds. Here’s a link to my blog post about using cardboard. https://blog.timesunion.com/gardening/cardboard-the-gardeners-friend/7188/