Knowledgebase
Yellowing and browning green giant #753162
Asked May 31, 2021, 10:01 PM EDT
I have 14 green giant 10ft trees and some are really changing color. Yellowing and some have brown in them. I’ve been watering 1-2 times a week and just added fertilizer 10-10-10 this past Friday. Here is a picture of one
Wake County North Carolina
Expert Response
Half were planted early winter 2020 and half early spring 2021. Heavy clay soil and most planted above ground in a mound of clay.
Tip browning on Green Giant Arborvitae can have several causes. There is an insect known as a arborvitae leafminer that will make a small hole in the tip of the needle and feed on the interior of the needle. Look for those small holes. Several different fungal infections can also cause needle browning. Small black spots may be observed on the affected branches. I'm concerned that you have planted most of these shrubs above ground. It is recommended that shrubs be planted with the root collar only slightly above ground level. The stress caused by improper planting can lead to tip dieback.
https://ipm.ces.ncsu.edu/2018/08/two-unusual-needle-problems-in-arborvitae/
https://www.extension.purdue.edu/extmedia/ID/ID-477-W.pdf
https://onslow.ces.ncsu.edu/2017/03/planting-trees-and-shrubs-correctly/
