Holly trees produce pointed leaves with serrated edges that stay on the tree all winter, accompanied by bright red berries. If leaves start dropping off of the holly tree, it is time to look at the cause and see what can be done.
Holly trees may start to drop their leaves due to a disease called holly leaf blight, or they may be responding to environmental factors, like intense cold. Scale insects, which leave behind sooty mildew, may also cause holly leaves to drop off.
Dealing With Disease
Improving the air circulation through the holly tree will reduce the proliferation of the spores. Raking up and destroying fallen leaves rather than composting them is recommended. Ground cover plants placed underneath the tree reduces the splash of rain back onto the tree's branches.
Dealing With Insects
The scale insects that produce black sooty mould on the tree's branches and leaves may be removed by hand, with a direct spray of water or with insecticidal soap.