Question
I planted two Westmont Arborvitaes about a month ago & have been watering them daily.  I noticed recently that they are turning brown in the interior of the plants.  the outside is mostly still green.  What could the problem be and what can I do to correct it?  I live in a hot desert climate.

Answer
Sounds like too much water. Over watering will cause the same symptoms as too little water--needles turning brown. I would water with 1 inch of water--place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Do this every third day unless it rains.

Also planting in the summer months is the worst time do tot he heat and dry weather. This causes stress on the young tree.  IF you have not done so much around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk (pine straw is good). This will help hold moisture around the roots.