Question
Is is all right to use pine bark mulch around Hostas?  thank you

Answer
Hostas love acidic soil.  Pine bark mulch is not as acidic as the actual pine needles, but it will not harm them. When I was living in Virginia, I would regularly mulch my Azaleas and Hostas with the actual pine needle duff.  They seemed to like it. Mulching is the geatly overlooked landscape booster for healthy vigorous plants.  

For Hostas, when planting in the fall where winters are severe, a winter mulch should be applied after the ground is frozen to prevent heaving.

For other ideas for shady, under pine tree locations try this link:  http://www.seedsofknowledge.com/pines.html