Experts and BHG readers answer.
Pyramidalis arborvitae going brown after pruning
Well I worry about your plants because when you shear an evergreen back to where it's brown, it rarely comes back again. You should never shear an evergreen that severely. Overgrown specimens should be only cut back by inches every year until you get them where you want them. A severe pruning like this fellow did to your plants may have actually killed them. There's not much you can do now except to see if they do come back. It's a shame they were cut so severely.