When I had a bog garden, the VFTs and Sarras did not need pots. They don't spread very fast at all. The drosera on the other hand may be a different story. If you're not careful, they may end up covering the whole area in sticky dew! If you intend to plant sundews like D. binata or D. capensis, pots might not be a bad idea.
The flip side of the coin is just to let it all go and see what happens. I rather enjoyed having d. spatulata surrounding my vfts. No insect got away! That's my experience at least.