Q.I Have Two Potted Hollies Outside. They Have Been Doing Well Except For Some Insect/fungus From Time To Time. New Growth Already
this year. Today, after a hard rain, I notice that they have dropped old leaves at an alarming rate. What is wrong? We live in East TN where the weather has been hot and I have not watered them as often as I should. Maybe this would cause the leaf drop? Generally, the leaves look to be lightening instead of being deep green and some have dark spots…not necessarily shriveled or brown, but just touching a stem will knock often several leaves….the older leaves, not the new growth. Also, I have sprayed them for insects and fungus. Drainage is good as well. Plants are about three or four years old.

Certified GKH Gardening Expert
It is likely stress related from the lack of water and hot days. Plants in containers are more vulnerable than those in the ground. Leaf scorch can also be a possibility, along with holly leaf spot. These articles should help:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/leaf-scorching-in-holly.htm
https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-leaf-loss-in-spring.htm