but to answer - it is still advantageous to have water, etc. pass through to the underlying soil otherwise you end up with standing water or pools and puddles. I like the idea of landscaping fabric far more than the actual thing - most DIY's do not install it correctly, it is not a cure-all for weeds. You will still have weed seeds sprouting from the mulch you spread but the can generally be easily pulled as their roots are necessarily shallow. Herbicides can also be used as others suggest but I'd reserve those and use only when necessary.
