Dying Japanese Hollies - Ask Extension
Hi All, I have a number of Japanese Hollie’s in my front yard and all of them suddenly have lot of dying patches this spring. Previously, most had b...
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Dying Japanese Hollies #894983
Asked March 20, 2025, 3:16 PM EDT
Hi All, I have a number of Japanese Hollie’s in my front yard and all of them suddenly have lot of dying patches this spring. Previously, most had been healthy looking. The two sky pencils have been struggling for a while. The two images show the issue. I’m assuming that the soil is not sufficiently acidic. We had to cut down a large tree in the front yard maybe 7 years ago and now they get much more sun and much less natural soil amendment than they used to get. Thanks for any direction in what I might do to treat whatever is happening.
Montgomery County Maryland
Expert Response
This might be mild winterburn (a very common phenomenon on evergreens) or possibly the beginnings of damage from Thielaviopsis root infection, which we find Japanese Hollies susceptible to, especially in soil that drains poorly or which isn't acidic enough for the preferences of the hollies. (It also might be an overlap of both issues, since the symptoms would look about the same.) A laboratory soil test can measure soil acidity (more accurately and clearly than home test kits for pH), though it can't diagnose suspected root infections.
Winterburn happens when foliage loses water through evaporation (as it does all year) that the plant can't replace quickly enough due to dry or frozen soil. Winter air, having very low humidity, and exposure to sun or winds can contribute to this damage. Winterburned leaves typically fall off on their own later in spring. While the affected leaves don't need removal by hand, you could trim off any branch tips that died along with them, as appears to be the case here. (Even if Thielaviopsis caused the tip dieback instead of winterburn, you'd still need to prune off those dead areas since there is no reversing the damage.)
Although some fungicides that drench the soil might suppress that particular pathogen, they are not practical to use, both because they don't always work (and they can't cure any existing infection), and because the organism is not uncommon and could recolonize the soil at any point in the future. That fungus tends not to be an issue, though, when soil conditions support healthy root growth and don't stress the plant, which predisposes it to infection. (In this case, that stress arises from soil that isn't acidic enough, is too wet too often, is overfertilized, or compacted and poor-draining. This is why fungicide isn't the answer, since it doesn't address the reason the plant succumbed to infection in the first place.)
This planting location appears to be adjacent to a driveway and house foundation, which tends to have compacted soil conditions and potentially insufficient acidity. Although there's not much you can do about that at this point, it's a consideration for plant care, since such areas tend to drain more poorly (any roof downspout outlet that empties nearby, flooding the roots?) and can also be hard to re-moisten once they get too dry. Maryland is still experiencing a pronounced drought that began about a year ago. Heat reflecting/radiating off of the brick and pavement could be exacerbating the situation, especially if the hollies weren't being monitored for watering needs last summer and autumn.
For now, just do some minor pruning and wait to see how the shrubs fare; this might be all the dieback they develop. Check them for watering needs periodically, and feel free to send in more photos if they worsen. (Though, admittedly, there will be little recourse in that situation, and they would probably need to be replaced if there is significantly more dieback in the future.)
Miri
Winterburn happens when foliage loses water through evaporation (as it does all year) that the plant can't replace quickly enough due to dry or frozen soil. Winter air, having very low humidity, and exposure to sun or winds can contribute to this damage. Winterburned leaves typically fall off on their own later in spring. While the affected leaves don't need removal by hand, you could trim off any branch tips that died along with them, as appears to be the case here. (Even if Thielaviopsis caused the tip dieback instead of winterburn, you'd still need to prune off those dead areas since there is no reversing the damage.)
Although some fungicides that drench the soil might suppress that particular pathogen, they are not practical to use, both because they don't always work (and they can't cure any existing infection), and because the organism is not uncommon and could recolonize the soil at any point in the future. That fungus tends not to be an issue, though, when soil conditions support healthy root growth and don't stress the plant, which predisposes it to infection. (In this case, that stress arises from soil that isn't acidic enough, is too wet too often, is overfertilized, or compacted and poor-draining. This is why fungicide isn't the answer, since it doesn't address the reason the plant succumbed to infection in the first place.)
This planting location appears to be adjacent to a driveway and house foundation, which tends to have compacted soil conditions and potentially insufficient acidity. Although there's not much you can do about that at this point, it's a consideration for plant care, since such areas tend to drain more poorly (any roof downspout outlet that empties nearby, flooding the roots?) and can also be hard to re-moisten once they get too dry. Maryland is still experiencing a pronounced drought that began about a year ago. Heat reflecting/radiating off of the brick and pavement could be exacerbating the situation, especially if the hollies weren't being monitored for watering needs last summer and autumn.
For now, just do some minor pruning and wait to see how the shrubs fare; this might be all the dieback they develop. Check them for watering needs periodically, and feel free to send in more photos if they worsen. (Though, admittedly, there will be little recourse in that situation, and they would probably need to be replaced if there is significantly more dieback in the future.)
Miri
