Does that stump always stay that wet? What's the diameter of stump? There are miniature phrags available.
There's a guy here, Akhenaten, who grows tons of different miniatures. You should look through his thread for ideas as well (link below). And I'm sure he'd answer any question you might have...
Project Phoenix
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PS And he has an extremely cool carnivorous plant called Utricularia pubescens, which might look really nice on top of that stump.