The mulch you want to describe sound the typical mulch you would give to a lawn adding alkaline & nutrients to the soil.

Sarracenia bogs are normally mulch with pine needle as the dormant season approaches, since pine needles become acidic & to protect the plants from the cold.

Here's a little site that can work for you: http://www.pitcherplant.com/care_sheets/sarrac_care.html

I second the motion with pine needles!

Pine bark would also work. If you are going to leave them outside during winter then pine needles would be the best.

thanks for the input. i believe i'll put down a good layer of pine needles and then a thin layer of bark down on top, just for ascetics.