Q: We have two large arborvitae’s at our home’s front entrance. Last night I was standing near one of them and heard a noise. When I looked at the bush, it was moving! Upon closer inspection my husband found the lower front section to be covered in bagworms. They have not made it to the top or even all the way around the tree yet. What can I do to bring the tree back?
A: It must have been really creepy to actually hear them feeding!
Here’s what I would do:
Remove all bags you can find. Wear gloves because arborvitae needles can be sharp. Drop the bags in a bucket of soapy water or destroy in some other way.
Spray the tree with spinosad (Captain Jack’s Dead Bug Brew). This kills the immature insects that haven’t made a bag yet.
Repeat picking and spraying in four weeks.
Remove any more bags in September but no spray is needed.
Fertilize your plants with Holly Tone or Dr. Earth or Osmocote.
It will take a couple of years but usually new growth on either side of the brown area will fill in if the plant is otherwise