Damage to trunks of rhododentrons - Ask Extension
This scoring or boring was noticed recently on one of our rhododendrons. The damage is present at differing heights, between 2-4 feet above ground.
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Damage to trunks of rhododentrons #922573
Asked December 01, 2025, 4:07 PM EST
This scoring or boring was noticed recently on one of our rhododendrons. The damage is present at differing heights, between 2-4 feet above ground.
Any help in ID of the perp would be appreciated.
Thanks in advance.
Kate Lowry
Benton County Oregon
Expert Response
Hi, Kate,
That is an unusual pattern of damage. Most causes would be more generally spread in patches, or vertical if it is animal damage. I really can't i.d. it for sure, but here are some ideas.
It could be from a buck rubbing the velvet off his antlers. The height is right, and they can move their antlers in a horizontal manner. Do you have deer in your area? If so I would consider this first.
It's possible it is gnawing damage, perhaps from a porcupine if you live on the east side. Most critters gnaw in a more vertical fashion, but I have seen pictures of some porcupine damage that slightly resemble this.
Also possible, but unlikely, is the larvae of a wood boring beetle. They generally make tunnels under the bark, but if the bark was pulled away, some of the marks on the underlying wood could be from beetles.
In any case, watch daily for any fresh damage. The timing may give you clues as to the culprit.
One last possibility is a string trimmer. From the photos, it doesn't look likely that one could approach the trunk easily, but if one has been used around it, particularly for trimming higher foliage, not grass, then it could well have made these gouges.
That is an unusual pattern of damage. Most causes would be more generally spread in patches, or vertical if it is animal damage. I really can't i.d. it for sure, but here are some ideas.
It could be from a buck rubbing the velvet off his antlers. The height is right, and they can move their antlers in a horizontal manner. Do you have deer in your area? If so I would consider this first.
It's possible it is gnawing damage, perhaps from a porcupine if you live on the east side. Most critters gnaw in a more vertical fashion, but I have seen pictures of some porcupine damage that slightly resemble this.
Also possible, but unlikely, is the larvae of a wood boring beetle. They generally make tunnels under the bark, but if the bark was pulled away, some of the marks on the underlying wood could be from beetles.
In any case, watch daily for any fresh damage. The timing may give you clues as to the culprit.
One last possibility is a string trimmer. From the photos, it doesn't look likely that one could approach the trunk easily, but if one has been used around it, particularly for trimming higher foliage, not grass, then it could well have made these gouges.
Thank you, Signe.
Although we certainly have plenty of deer in our area of Corvallis (Northwest) and bucks have damaged a shrub in our front yard, our back yard (where this rhododendron is located) is securely fenced and we have never seen a deer inside the fence (knock on wood...). So I think that rules out deer as the culprit.
I would LOVE to see a porcupine, though we are not located on the east side. However, we do have a game camera and I will relocate it so that we can monitor the plant. We have observed raccoons, rats, foxes, skunks, possums, nutria, and neighborhood cats in the back yard in the past using the game camera. I considered Red-bellied Sapsucker, but we've never seen one on a rhododendron and these are not their usual pattern of wells but rather linear defects.
Although string trimmer is a reasonable thought, we don't use one and the height would seem to rule that out.
It seems then that some kind of wood boring beetle tops the list of possible suspects. We will monitor the situation and observe for further damage.
Thank you again for your thoughtful reply!
Kate Lowry
On Tuesday, December 2, 2025 at 12:20:03 PM PST, Ask Extension wrote:
