UNITED STATES—Palm trunks grow in only one direction; upward, toward sunlight and away from gravity. Each trunk is equipped with only a single terminal bud. If that bud encounters an obstacle, it can not be pruned around it. Palm trunks that get get too close to high voltage cables, or that might sway too close with a breeze, must therefore be removed to maintain minimal clearance from the cables.
Queen palms are notorious for getting planted under high voltage cables because they are so often impulse purchases that get planted without much planning. They are popularly planted along rear fences, exactly where high voltage cables are often located. Mexican fan palms often grow along rear fences as well because that is where birds and rodents are likely to drop the seeds.
Trees with single central leaders, like redwoods, spruces and certain pines, will be disfigured if their main trunks need to be topped for clearance from cables. Removal of such trees is often more practical than this sort of disfigurement. More extensively branched trees like sycamores, ashes, oaks and elms, are more adaptable to clearance pruning if it is not too severely disfiguring.
It is much simpler to not plant trees that get too large under high voltage cables. Elsewhere in the garden, where there is enough lateral (side) clearance, vertical clearance is not such a problem for larger trees. Small trees like redbud, purple leaf plum, photinia and various pittosporums, either do not get tall enough to reach upper cables, or will require only minimal pruning for clearance.
Below high voltage cables, the lower cables are for lower voltage, telephone and television. ‘House-drops’ are the cables that extend from utility poles to houses and other buildings. Although clearance is not so important for these lower risk cables, limbs that lean on them and blow around in wind can be abrasive. Sagging limbs can cause utility cables to sag more than they should. Unfortunately, those who prune trees for utility clearance are efficient, but rarely arboriculturally correct.
As a shorn evergreen hedge or simple shorn shrubbery, photinia, Photinia X fraseri, produces handsomely glossy bronzy red foliage without bloom. It is best if shorn as weather warms at the end of winter, and then allowed to grow out for a while. It can be shorn again through summer as bronzy foliage fades to green, but should not be shorn so often that it is always deprived of red foliage.
Without regular shearing, photinia becomes a small tree or large shrub. Trees can either be staked on single trunks, or allowed to develop multiple trunks. New growth in spring is not as vigorous as it would be in response to shearing, so is not as colorful. Domed trusses of tiny white flowers bloom about as soon as new foliage appears. The floral fragrance can be objectionable to some.
Only the biggest and oldest trees reach high voltage cables. Most stay less than 15 feet tall and broad. Hedges can be kept less than six feet tall, and ideally, should be kept less than half as deep (from front to back). Photinia can grow rather well while young, but then grows slower as it matures. Partial shade or a lack of water through summer compromise foliar color and density.