Ugh, over the past couple of weeks I've been having some mysterious dieback on my collected Yaupon holly. It was collected in late winter and is planted in garden soil. It's been growing strongly up until this point. I've had 3 branches die and additional twigs are starting to show the same symptoms. My first thought is spider mites - I found some fine webbing around the apex where some of the dieback is occurring. Other growing tips are normal and going strong. There hasn't been a change in watering or whether really. It's been hot, but that's nothing new. Any ideas? I sprayed with Bayer Advanced 3-in-1 disease, insect, and mite control a couple of days ago. I plan to spray on a 7 day schedule.