So sorry but it looks to me like your boxwood have a classic case of boxwood leaf minor. Tiny flies or midges lay eggs under the leaves, they hatch and the larvae burrow under the first layer of the leaf feeding until they become adults and fly off. Prune now in early spring to remove the egg infested leaves before they hatch. Cut back as much as you can without going into woody stems. Do not compost the infected pruning crumbs. Next apply a systemic insecticide that will go onto the soil and be sucked up by the plant to make them poisonous. You can also spray Orthene onto the boxwood but you must time the spray to when the adults have formed to be effective. The best way tot do this is notice when the Weigela shrub is in bloom as that will tell you when the flies are mature. Visit a nursery if there are no weigela shrubs in your neighbor hood. The good news is that with fertilizer such as Osmocote added to the soil your boxwood may outgrow the damage. If you boxwoods continue to turn brown you may want to consider a substitute plant for your hedge such as Japanese Holly which looks similar to boxwood or Euonymus fortunei \'winter creeper\' if you want a low hedge. Go get snippy with those boxwood now and give them a fighting chance. Keep growing, Marianne Binetti