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arborvitae rushmore problem after winter #555039

Asked April 22, 2019, 6:05 PM EDT

I planted 3 arborvitae 'rushmore' this past June. The trees looked great thru the fall. They were wrapped with burlap for the winter and when unwrapped this spring the bottom half of each tree is basically gone. Any idea what could cause such a thing? The tops look great!

Hennepin County Minnesota

Expert Response

This is a very unusual picture.
My first reaction is that this is a kind of winterburn to which arborvitae are especially susceptible. https://hort.extension.wisc.edu/articles/winter-burn/  However, the repetition of the injury to all three trees suggests something happened in the wrapping or shading of them.
A couple questions.
What direction is the camera facing?
What were the trees wrapped with?  Or did you use a barrier to protect them?
Was there a snow drift against the trees?  Was there something like a small runabout that shaded the trees?
Did other kinds of plants on your property have animal damage?  I did find this picture of deer damage to arborvitae.  https://gardening.stackexchange.com/questions/11226/will-arborvitae-regrow-to-their-usual-shape-after-being-partially-eaten-by-deer

"Protect plants during the winter.  Use burlap, canvas, snow fencing or other protective materials to create barriers that will protect plants from winter winds and sun. Install four to five foot tall stakes approximately two feet from the drip lines of plants especially on the south and west sides (or any side exposed to wind) and wrap protective materials around the stakes to create “fenced” barriers. Leave the top open. These barriers will deflect the wind and protect plants from direct exposure to the sun. Remove the barrier material promptly in spring. DO NOT tightly wrap individual plants with burlap as this can collect ice, trap moisture and make plants more susceptible to infection by disease-causing organisms. Use of anti-transpirant products to prevent water loss from foliage over the winter has been shown to have limited benefit. These materials degrade rapidly, require reapplication after each significant rain or snow event, and may not be effective in preventing water loss that can lead to winter burn."

A barrier is suggested on the UMN page. https://extension.umn.edu/planting-and-growing-guides/protecting-trees-and-shrubs-winter#how-to-reduce-evergreen-winter-injury-1264311 "Construct a barrier of burlap or similar material on the south, southwest, and windward sides of evergreens. If a plant has exhibited injury on all sides, surround it with a barrier, but leave the top open to allow for some air and light penetration. Surround your young plant with a few wooden stakes, allowing a few inches of space between the stakes and the plant. Lay burlap over the stakes and secure it with staples. Don’t allow the burlap to touch the foliage. If it gets wet and freezes, it can damage the plant.
Is it possible that the base was wrapped so tight it damaged the branches, this also makes them more prone to disease and insect issues with no circulation, looks like the tops did not have the burlap. If you can find a proper burlap barrier visual link to send that may give them the idea.

thanks Steve! In this new picture the camera is facing south. There is a fence on the west side of the trees and a patio/walkway on the east side. The trees were wrapped lightly from bottom up to the top. The snow was about 2/3 the way up the new bare part of the trees. No deer. No other plant damage. The trees were really looking good going into the winter. Could rodents do this kind of damage? Or rabbits? Wouldn't the tops show some stress if it were winter burn? It's very strange that all three look the same. Thanks for your opinion.
The Question Asker Replied May 27, 2019, 10:29 AM EDT
It is an interesting question about rodents. One person who I spoke with about this says that moles or voles might have been feeding on the lower two thirds of the plants.  It sounds like that would match the level of the damage.  I would suspect however that you would see other evidence of their tunneling. 

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