Question
Hello,  Two years ago we planted 20 4 foot emerald green arborvitae.  We water once a week for 6 hours with a soaker hose.  The bottom branches have turned a sooty looking grey.  They eventually turn brittle and fall off.  Please help.  Some branches are brown also.  Thank you.  John R. Steffes Sr.

Answer
John:
You may have a foliar disease. There are several fungal organisms that can attack the leaves.  If all of the plants are doing this, there may be another factor- like shading of the lower portions.  Deep shade can cause thinning.  It is best to have someone actually see some of these "sooty" twigs. Consider taking a few twigs to your local nursery for them to have a look see.

Hope this helps with your detective work.

Steve