Pruning:

• Arborvitae generally need little to no pruning.
• They may be pruned anytime except during sub-zero weather. The best time is early spring before new growth.
• The best pruning method is to cut individual branches back to an upward-growing side branch. This pruning method is time-consuming but keeps the plant looking young and natural.
• Any pruning that tapers in towards the bottom of the plant will lead to thinning of the lower branches due to shading. To keep the bottom full, the base of the shrub needs to be wider than the top portion.
• It’s common to see arborvitaes that have overgrown their space. Since new growth comes ONLY from the growing tips, branches cannot be
  pruned back into the wood without needles. If the shrub is pruned back to bare wood, it will have a permanent bare spot.