Thuja Green Giants: Dead or Alive?

Asked April 20, 2019, 4:34 PM EDT

We planted a row of Thuja Green Giants from fastgrowingtrees.com last year. We watered them a few times in the winter, but man do they look dead. Some of them will drop "leaves" when touched. We were told that it would turn golden brown in the winter, and not to worry, but this can't be right. We've been watering more heavily the last few weeks, but it is not looking good. Are these dead? What went wrong?

Weld County Colorado

3 Responses

Hi, this is Steve, and thanks for contacting Ask An Expert with your question. One way to determine if a woody plant is dead it to do a scrape on a branch or stem with a fingernail or knife. Scrape back a small piece of bark as if you were scrapping the peel from an apple. If there is green material just under the surface, the plant is alive. You may need to keep moving down the stem or branch if you do not encounter green material and/or try multiple sites on the plant. If your plant is dead, it would be very difficult for us to determine the cause. Winter watering was a good practice on your part. These plants can be susceptible to winds which cause them to dry out much quicker than we would think. I’m including a fact sheet on Thuja for the Denver area, which is not significantly different than our area in this case.

https://articles.extension.org/pages/42059/will-the-thuja-green-giant-tree-thrive-in-denver-colorado-wed-like-an-evergreen

If you have any other questions, please don’t hesitate to contact us. Good luck.

I did the test. One looks green but another yellow. Is the yellow one dead?

The brighter the green the better, however, I would still give the plant more time to tell us for sure. Also, if you wish, Master Gardeners staff the Weld County Extension Office M/W/F from 9am-1pm. You could bring the pictures and pieces of these plants (green and yellow) for them to examine. The office is in Island Grove Park. Either way though, you should know in a month or so if there is life within the plants.