First I did not do this, my father did, really. He wanted to fert his arborvitae so he applied some fert he had kicking around. The fert contained 2,4D. It was rated at 5 lbs per 5,000 sqft. He applied 10 lbs per 1000 sqft. The arborvitae are appx 12 ft tall, healthy and established. Any suggestions on what we should do or should we just hope for the best. Thanks for any input.