Question
My 3 holly bushes are yellowing from the center out.  The stems are turning yellow on the center one.  Now the other two who were healthy last years are getting yellow leaves.  They are 3 years old.  No signs of bugs.  Can too much holly tone burn the plant.  or can too much water hurt them?
Clare

Answer
Clare,
If you mean that that the inner growth of the Hollies is yellowing, then this is a normal occurance. All evergreens drop their third or fourth year growth as the new growth emerges. These older leaves are no longer needed for food production, so they are discarded.
If it is the outer growth that is yellowing, then there are several conditions that could be causing this. Too much high nitrogen fertilizer can burn the roots if not watered in. A poor drainage condition that is allowing the shrubs to sit in puddles for too long can cause root death as well. It could also be a leafspot disease.
I hoped this helped.
Good luck.
Ed Gullisken