What happened to my Arborvitae evergreen?
Bought two of these bushes in the Spring (photos attached), just discovered that one is in bad shape, the other is thriving, both planted at the same time, same method, in the same bed. Can you make a determination from the photos? Any advice is appreciated.
Given that these were just planted, we would think that this is a failure to establish.
There are multiple factors to consider, and you will need to do some sleuthing to get clues.
These include being planted or mulched too deeply (mulch should only be 2-3 inches deep and always pulled back from stems/trunks of plants.) You should be able to see a gentle flare where the roots meet the trunk before it goes into the ground. Look closely for any damage (like gnawing from rodents) on the trunk. Voles can sever roots from beneath- gently pull on the plant.
How well does the soil drain there? With all the rain we have had, lots of plants with poor drainage have perished.
Finally, these plants need full sun.
Take a look at this page from Ohio State with cultural information for Arborvitae: https://hvp.osu.edu/pocketgardener/source/description/th_talis.html