Green Giant arborvitae dying; suggestions?

Asked June 25, 2018, 2:47 PM EDT

Steve is out of the Mat Su office for a few weeks, I am not sure my arborvitae have a few weeks to hang on (the ones that might survive). Does anybody have any suggestions as to what might be happening. The row on the left are Green Giant arborvitae. The row on the right are a smaller variety. Both were planted in 2016 and have done ok. This year they are dying. The Green Giants are hardest hit. I do not see any infestations. The soil is not waterlogged (and on a slope). I am outside of Palmer. Previously BIrch and wild rose grew here. This was tilled and new topsoil etc. I have additional photos.

Matanuska-Susitna Borough Alaska

1 Response

Arborvitae of all types are susceptible to desiccation (drying out) over the winter months, causing browning/death of parts or even entire plants/trees. Even longstanding trees can seem mysteriously injured under specific winter conditions such as low snow cover combined with cold dry winds.
I recall hearing from colleagues in your region that it was a tough winter in that regards and it was even so here in Southeast Alaska where we too are seeing a lot of arborvitae family damage in both well established and newly planted landscaped areas.
If the soil conditions are as optimal as possible (assuming you have done a soil test as well to determine proper pH, soil depth, hole size, etc.), then other strategies such as wrapping trees with burlap can definitely help when they are at sizes where that is feasible.
Most of the material that looks dead, probably is dead at this point in the season, so after you confirm with a little careful pruning that is true, you can prune off the dead material. Depending on your need and ability to develop your hedge row there, I would expect that replacing the most heavily damaged trees with be in order and winter protection will help reduce your loses.
Good luck and please let Steve know to send me a note if he has some other pieces to add.