Question

hydrangea tree   QUESTION: Until about 2 weeks ago, all 3 of my hydrangea trees were doing well and are now flowering.  All of them, but one in particular has started to drop yellow leaves from the centre.  I looked and though I saw spider mites so I sprayed with insectical soap.  Now the leaves have turned brown and are dropping at a faster rate.  I have a feeling that the brown leaves are from the spray.  I waited til evening, no sun to spray so not sure what happened.  What would have caused the intial yellowing of the leaves?  I have attached a picture. Thank you for your time.

ANSWER: Elizabeth:
The soap should be safe if it was mixed and applied properly. Could the soil be dry? Not enough OR toomuch water could produce these symptoms. I also saw leaf edges that were brown- drought can cause this. I don't think this is a contagious issue.

Steve

---------- FOLLOW-UP ----------

QUESTION: I bought the ready to use spray and applied it when there was no sun, as instructions but I find it strange that it turned the leaves brown and they fell off.  The brown edges were from the spray.  Until I used the spray the leaves were yellow.  So you say it is either too much water or not enough?  How is the best way to tell if the hydrangea tree needs water.  I water my hydrangea plants every day and they are thriving. Do hydrangea trees require more or less that hydrangea plants?

Answer
Elizabeth:
Looking at the soil around the root zone can be a clue.  Use a small spade to dig down a few inches.  It should be just moist to the touch, not sift through your fingers.  Trees often are sometimes slow to show the effects of drought. Hopefully, this is a temporary stress.

Steve