I planted two 6-foot cherry laurels in November of last year. I prepared the beds using Tropical John's bed preparation recipe, distressed the outside of the root ball somewhat and sprayed the root ball with Garrett juice. Before the cold weather set in, the leaves started turning brown and had red dots on the underside. Now all the leaves on one of the two bushes are totally brown and on the other about half of the leaves are totally brown. Does this mean they are totally gone or might they recover?

Sounds like you had spider mites on them. You can do a scratch test on the trunk and branches to see if they're still green. Treat the mites asap and make sure that you're sprinkler system is not hitting the leaves constantly when you water.

Thanks for the help! What is the preferred treatment for spider mites?

You can use soap to get them off, and hopefully if the watering situation is resolved, you won't have them problem any longer. Fertilize them well and make sure you are saturating the root ball when you water. Water deeply and less often.