How to keep weeds from overgrowing newly planted perennials.

So I’ve been having some bad luck with trying to establish perennials in the more “foresty” part of my property. I’ve tried planting blueberries, honeyberries, raspberries, asparagus and some other stuff. But even with mulching they get so overrun with weeds that they end up not thriving and just being choked out. Meanwhile online everyone seems to just plant things randomly in similar overgrown forest/field settings and those do seem to thrive? am I doing anything wrong and should I just cut the weeds very regularly then?