Young Arborvitae Suddenly Turn Yellow

Question From: D. Pavey - Manilla, Indiana, United States
Q: Nancy, I planted 30 green giant arborvitae in April of this year. I live in central Indiana and the trees were from the Arbor Day foundation and about 6-12 inches tall. 3 died shortly after planting and I was not surprised to lose a couple. However this last week I have had 3 more that turned completely yellow almost overnight. The strange thing is they were the ones that had been doing the best (tallest, greenest, and fastest growth). All 30 are planted in a row with mulch and a white plastic tree protector around them to shield from intense sun, wind, pests, and to help them stand up. I am just worried I have a mite problem that will take all of the trees. I did not see any mites when I checked but did notice very small spider webs on the foliage of the yellowed trees but I have also noticed regular (non mite) spiders around the tree. What your thoughts and what should be my next step- treat the affected trees, treat all the trees, remove and destroy the affected trees, or look at different problem? Lack of rain is not a problem for us right now. Thank you,

A: Mites are almost undetectable from the naked eye. Hold a white piece of paper at the base of the tree and shake it. If you see dark speckles (tiny) you have mites. Your trees are bare root and need almost daily watering for the first few weeks, especially in the heat. Hopefully you did not add any fertilizer to the planting hole. Not sure about the plastic tree protector. A picture of that would help. Evergreens rarely experience sudden death. Any chance you have been using chemicals in the area. Fertilzers or pesticides? Best And Happy Yardening, Nancy