We mulch everything here in southeast Pennsylvania. It does four things:
1. Looks good.
2. Keeps weeds down to a minimum.
3. Holds moisture.
4. It augments the soil, after a few years, the soil is rich with organic material.
Indiana Karen is right, after the initial “heavy” layer is applied it only needs a thin coating every spring to look brand new again.
A few years ago I began using what is sold here as “double ground.” It does not have the big chunks of wood in it that I would find before, although it is still coarse enough that it does not break down in one year.
My pond has river jack along the “front” edge and the other three sides are mulched right up to the rock border. The mulch does get into the pond a bit after a heavy rain. However, it floats and what lit bit does get in, ends up in the skimmer debris basket.
I have never used landscape fabric under the mulch, but in other applications, as miguynmkoi stated, it disintegrates quite rapidly.
I also had never heard of “Preen.” Something I will look into (although weeds in the mulch are not much of a problem, there are always a few). I do agree with Kittyzee, I would be very cautious with it around the pond, particularly if the landscaping is level with or higher than the pond.
