· Brooks Wilson's Answer
· Steven, I have noticed over the years that Sky Pencil Holly get a condition called dieback. This is common in many plants. Dieback first shows up with a few branches turning brown. If the branches are not removed the dieback will spread to all other branches. It usually take a month or two for the plant to totally die. I had a customer bring back a Sky Pencil a few years back that had dieback. I gave him a new one. I pruned the infected branches off and planted it in my landscape. The plant is thick and full and about 3' tall. Dieback results in a canker somewhere along a stem. The canker blocks the flow of nutrients to the branch. It's best to trim the entire branch off or at least prune it off about 6" below the canker. The canker looks like a knotted up area along the stem. It's east to locate due to the fact that the stem will be dead back to the canker.
Other problems could include root rot or fungus. If the plant is overwatered or planted to deep root rot can set in. Root rot usually takes 2-6 months or longer to kill a plant. The plant will usually start browning at the tips of the leaves. Slowly the plant will totally die. Fungus on the stems and/or leaves could also be the problem. Did you spray the plants with a fungicide? Fungus could kill the plant in 2-3 weeks or longer, sometimes taking months.
Hope this information was of help.)