I don't know the homeowner in question, but from my seat in the peanut gallery, I think I have grasped the basic plot outline. The homeowner has no interest in gardening. Nevertheless, he has some pride and, in any case, property values must be maintained and neighbors appeased. So off he goes to Home Depot or Lowes in search of an easy-care evergreen. He returns with five Sky Pencil hollies and, as Act I ends, plants them in the front yard.
In Act II, all five hollies are showing signs of stem dieback, which gets progressively worse as the weeks wear on. Act III: the five hollies are now thoroughly dead. The homeowner removes them but vows to persevere. In Act IV, four fresh Sky Pencil hollies are installed in the front yard. How will Act V end? Alas, poor homeowner.
A cultivar of the ever-popular Japanese holly (Ilex crenata), "Sky Pencil" grows 8 to 10 feet tall in a narrow column - no trimming needed. It looks great as a vertical element in the garden and in containers. Hardiness reports vary; I have seen it listed as zones 4-9 (highly suspect, if you ask me), 5-7, 5-8, and 6-8. But for those of us in the south, what is more relevant is that Japanese hollies do not like heat. NCSU's Plant Pathology Extension calls ilex crenata among the more disease-prone hollies, and judging from the dieback epidemic in my neighborhood (to say nothing of the plaintive queries on internet garden forums), I think they might be right.
Of course, "dieback" is not a terribly specific or helpful diagnosis, since it could be caused by any number of factors. And if you are an amateur gardener like me, good luck trying to figure out what those factors might be. Fungi, bacteria, nematodes, and excess moisture are only some of the possibilities. I'm sure the heat doesn't help either.
But enough about why - the important thing is to stop it. What I have found is that if I cut off the dead stems the instant I spot them, the disease does not spread to the rest of the plant. Problem solved. It's shockingly simple, really.
In truth, I have no idea if this remedy would work on all cases of dieback. Perhaps different causes call for different solutions. All I know is that none of my Sky Pencils have died since I stopped treating them like background scenery and actually started tending them.
Remedial plant care. What a concept.