Roots should work similar to all other AoE's, considering they don't though it's more indicative that roots are broken.
The Visual effects should and probably do work the same as all the other visual effects though, which is to say they wouldn't be visable on the target if they were concealed.
Nothing in the root description implies they should be able to break concealment, nothing in any AoE's description implies any of them should break concealment. There's no logical or RP reason which can't be easily countered as to why they should break concealment, and the AoE roots all have under 100% NR Check which is quite frankly broken as well.