What is the issue with my Holly Nellie Stevens-8 years old - Ask Extension
The lower branches are becoming dead with each passing year and there isn't dense growth on the upper canopy. It receives full sun and on an irrigatio...
Knowledgebase
What is the issue with my Holly Nellie Stevens-8 years old #864270
Asked April 12, 2024, 2:41 PM EDT
The lower branches are becoming dead with each passing year and there isn't dense growth on the upper canopy.
It receives full sun and on an irrigation system. I do notice some larger black patches and smaller white patches on the bark- Picture attached.
Loudoun County Virginia
Expert Response
Thank you for your questions and photos of your Nellie Stevens Holly.
It is commonly difficult to give a precise diagnosis from photos alone, however, our best guess is you have a problem with Phytophthora Root Rot.
This is spread by fungal spores that may have entered the tree through broken branches or bark. It is commonly linked with root rot.
We are concerned that root rot may be a problem with this tree given that it is irrigated and has an apparently heavy layer of mulch up to the trunk of the tree.
The whitish gray spots on the trunk appear to be lichen. This should not be a problem. But we are quite concerned about the larger darker areas around the trunk at the base of the tree. These appear to be the phytophthora infections.
Do you see any signs of spotting on the leaves?
Are the leaves on the declining branches rapidly dying before you cut the branch off?
Unfortunately, once this fungus has infected the tree, it can be very difficult to control.
Here is a brief description of the fungus and a citation of a Clemson University extension publication with a bit more information.
Phytophthora Root Rot: The water mold fungi, Phytophthora cinnamomi, and other Phytophthora species cause root rot on hollies growing in very poorly drained sites or wet areas. Planting too deeply and over-mulching may also contribute to disease development. The symptoms of this disease and black root rot are similar. Typically, yellowing of the leaves (particularly at the shoot tips), early leaf drop, slowed plant growth, and twig dieback are seen at early stages of the disease. Later, one or more limbs may wilt and die back to the main trunk, and a brown to black streak of dead tissue may extend from one area of rotted roots to the damaged limb. Often, the root system will continue to disintegrate until the plant dies.
https://hgic.clemson.edu/factsheet/holly-diseases-insect-pests/
Given the seriousness of this problem, and the size of your tree, we suggest you consult an ISA certified arborist about this diagnosis and whether you can save this tree. You can identify an option at the following website:
https://www.treesaregood.org/findanarborist/findanarborist
Sorry for this difficult diagnosis, but we hope this helps.
Kind regards
David
It is commonly difficult to give a precise diagnosis from photos alone, however, our best guess is you have a problem with Phytophthora Root Rot.
This is spread by fungal spores that may have entered the tree through broken branches or bark. It is commonly linked with root rot.
We are concerned that root rot may be a problem with this tree given that it is irrigated and has an apparently heavy layer of mulch up to the trunk of the tree.
The whitish gray spots on the trunk appear to be lichen. This should not be a problem. But we are quite concerned about the larger darker areas around the trunk at the base of the tree. These appear to be the phytophthora infections.
Do you see any signs of spotting on the leaves?
Are the leaves on the declining branches rapidly dying before you cut the branch off?
Unfortunately, once this fungus has infected the tree, it can be very difficult to control.
Here is a brief description of the fungus and a citation of a Clemson University extension publication with a bit more information.
Phytophthora Root Rot: The water mold fungi, Phytophthora cinnamomi, and other Phytophthora species cause root rot on hollies growing in very poorly drained sites or wet areas. Planting too deeply and over-mulching may also contribute to disease development. The symptoms of this disease and black root rot are similar. Typically, yellowing of the leaves (particularly at the shoot tips), early leaf drop, slowed plant growth, and twig dieback are seen at early stages of the disease. Later, one or more limbs may wilt and die back to the main trunk, and a brown to black streak of dead tissue may extend from one area of rotted roots to the damaged limb. Often, the root system will continue to disintegrate until the plant dies.
https://hgic.clemson.edu/factsheet/holly-diseases-insect-pests/
Given the seriousness of this problem, and the size of your tree, we suggest you consult an ISA certified arborist about this diagnosis and whether you can save this tree. You can identify an option at the following website:
https://www.treesaregood.org/findanarborist/findanarborist
Sorry for this difficult diagnosis, but we hope this helps.
Kind regards
David
