Question
I just recently planted 18 Emerald Green Arborvitae trees (planted in May 2004) and they are all yellowing in the center, is this typical for the fall?  They have not been overwatered, I am at a loss as to what to do.

Answer
JoDee,

These plants should not be yellowing in the center. This is not a response to fall.  I am suspecting that they need water.  I suspect this from your statement that you know they have not been over watered.  Plants,and especially evergreens, need adequate moisture going into winter.  When evergreens die over the winter it is referred to as winter kill, but in reality many of these plant die from drought having dried out over the winter.  I would water these plants.  

You also might want to take a soil sample to your local extension office for analysis in case there is something nutritional.

Good luck

Gary