Almost all photinia in local landscapes is Fraser’s photinia, Photinia X fraseri, which is a thornless and fruitless hybrid of two species that are now rare. Some of the old fashioned photinia are thorny. Some produce copious berries that can get messy, or feed birds who can get messy. More modern cultivars of Fraser’s photinia are becoming more available.
Fraser’s photinia is popular as a shorn evergreen hedge. New foliage that develops after shearing is richly reddish bronze, and fades to dark green. Bronze color is best in spring, after late winter shearing. Summer shearing stimulates a repeat performance, although it may not last as long before the foliage fades to green. Shearing enhances foliar density.
Unshorn photinia can develop into small trees as tall as fifteen feet, with new growth that is a bit less richly colored than that of shorn photinia. It also blooms, often profusely, with big and rounded trusses of tiny creamy white flowers. Bloom is not impressively colorful. Floral fragrance is objectionable to some. All photinia types are susceptible to fire blight.
Mowers are for mowing lawns and shallow ground cover. Blowers are for blowing debris from pavement, decking and other flat surfaces. The names of these tools suggest these particular functions. Those of us who use such tools tend to be aware of their limitations. Why are simple concepts of shearing and the associated tools so difficult to understand?
‘Mow, blow and go’ gardeners are not so bad if they simply mow, blow and go. They tend to the two most significant but also least pleasurable tasks in the garden, and then leave before causing problems. Most are also qualified to add bedding plants or shear hedges. However, some will shear anything that is within reach of their powered hedge trimmers.
Shearing is for hedges or shrubbery that is strictly foliar. There are few exceptions. Such shearing should be performed properly, and only for the few plants that are conducive to it. The process promotes foliar density, but also generally inhibits bloom. For hedges that function as living fences in the background of more interesting plants, this is no problem.
Otherwise, shearing plants that are not conducive to it ruins appealing form, and inhibits or prevents appealing bloom. Privet and photinia perform well as shorn hedges because their dense evergreen foliage is their primary asset. Their bloom is actually undesirable. Their natural forms are unremarkable, but their shorn forms can be remarkably practical.
Frequent or untimely shearing prevents lemon bottlebrush and oleander from blooming. However, shearing immediately after a bloom phase stimulates new growth to bloom for a subsequent phase. New growth only needs an opportunity to mature and bloom before removal. Such potentially blooming stems need extra space to extend prior to blooming.
As practical as it is for hedges, shearing ruins the foliar texture of other plants. Heavenly bamboo is worthlessly shabby without its naturally intricate foliar texture. Juniper retains good color, but becomes boringly plain. Rhododendron and hibiscus become disfigured and can not bloom. Each of these plants and all others are discriminating about pruning. Few are agreeable to shearing.
Where it had been left to develop naturally in old freeway landscapes, shiny xylosma, Xylosma congestum, grew as small trees. The largest are significantly taller than twenty feet. They can be pruned up to expose their nicely flaking bark on sculptural trunks and stems. The evergreen foliage is shiny and rather yellowish green, somewhat like that of camphor tree. The slightly serrate leaves are about two inches long or a bit longer. The tiny and potentially fragrant flowers are rarely seen, and not worth looking for. In refined landscapes, shiny xylosma is popular as a shorn hedge. Xylosma congestum ‘Compacta’ has denser growth, and can be kept only a few feet high if necessary. Vigorous shoots can have nasty thorns hidden in their deceptively gentle foliage. Once established, shiny xylosma does not need much water. It prefers full sun exposure, but will tolerate a bit of shade.
All the wrong plants get shorn. Mow, blow and go gardeners are known for shearing everything that they can reach into creepy and unnaturally geometric shapes, usually flared out at the top, and bulging obtrusively into otherwise usable space. Yet, functional formally shorn hedges are passe and almost never shorn properly.
First of all, a formal hedge should be uniform, which means that all the plants that comprise it should be the same, and planted at the same distance from each other. Any plants within a formal hedge that die should be replaced with the same plant. A single English boxwood plant added to a Japanese boxwood hedge will always stand out with a different shade of green and growth pattern. Seedlings of other plants that grow up into a hedge should be removed before they become part of it.
Secondly, a formal hedge should be contained within defined boundaries. It should get neither too tall, nor too deep (from front to back). A fat hedge wastes space. There is no excuse for a hedge to encroach obtrusively over walkways, driveways or patios.
The vertical faces of a hedge should be completely vertical or slope very slightly inward at the top, but should certainly not slope outward to shade lower growth. A slight inward slope is more important on a northern face of plants that are sensitive to shade.
Hand pruning hedges (with hand shears) produces the best finish, but takes quite a bit of time for big hedges. Shearing with typical hedge shears cuts leaves as well as stems, so can cause foliage with large leaves to look a bit tattered for a while. Hedges that grow fast may need to be shorn twice or more annually. Some hedges can get shorn back aggressively once annually, and then allowed to fluff out evenly through the rest of the year. Bottlebrush and escallonia hedges can bloom nicely and evenly if shorn only once annually.
Glossy and wax leaf privet are among the most traditional of formal hedges. Glossy privet can get quite tall, but wax leaf privet actually has glossier foliage. Photinia and shiny xylosma have a bit more color, but want a bit more space (from front to back). Boxwoods make very nice small hedges. Pittosporums are available in various shapes and sizes. Pittosporum eugenioides gets quite tall, and can be kept quite lean. Pittosporum tobira is shorter and wider.
There are too many other plants known as ‘mock orange’ for Pittosporum tobira to still go by that name, which is why it is more commonly known by its Latin name, or simply as ‘tobira’. The pleasantly fragrant flowers do not smell too much like those of orange anyway. The glossy and dark green leaves are like those of some hollies, without the distinctive prickly points. ‘Variegata’ has lighter green foliage variegated with white, but does not bloom as much. Dwarf cultivars, both variegated and unvariegatd, bloom even less. ‘Variegata’ has a tendency to occasionally produce stems of green (unvariegated) foliage that grow more vigorously and can overwhelm the original variegated growth if not pruned out. Common green Pittosporum tobira can grow as a small tree in the partial shade of larger trees, but is more often maintained as dense shrubbery less than ten feet tall. It makes a nice dense hedge in full sun, but unfortunately does not bloom if shorn regularly. All cultivars are resilient to drought once established.
Good old fashioned boxwood hedges really look silly if just a single missing plant get replaced with a different cultivar (cultivated variety) or specie. Most of the older boxwood hedges are the traditional, but somewhat yellowish Japanese boxwood. Most middle aged hedges are a relatively newer cultivar that is a bit greener. Modern boxwood hedges are more likely a cultivar of English boxwood, Buxus sempervirens.
English boxwood resembles Japanese boxwood, but has slightly narrower leaves that produce a slightly more objectionable aroma when shorn or otherwise disturbed. These opposite (paired) glossy leaves are only about a quarter to half an inch wide and about twice as long. The color is slightly darker with a more ‘olive’ tone. Wild English boxwood in Europe can grow as small trees. Most garden varieties are fortunately much shorter and more compact, which is why they are so popularly shorn into small formal hedges. They also do well as topiary. ‘Aureo Variegata’ is variegated with nicely contrasting cream colored leaf margins.
It is difficult to know how big any of the various cultivars of English yew,Taxus baccata, will eventually get, and how long they will take to get that big. Most can get almost as tall as thirty feet. Some can get nearly twice as tall. However, they can take more than a century or several centuries to do so. Old specimens around Europe are significantly older than two thousand years. Slow growth is an advantage for formal hedges that get shorn only annually. English yew prefers regular watering. Partial shade is not a problem.
Irish yew is actually a cultivar of English yew with densely upright growth. The various golden yews have yellowish foliage. Otherwise, most English yews have finely textured dark green foliage on angular stems that resemble those of redwood. Individual leaves are very narrow, and only about half and inch to an inch long. The peeling dark brown bark resembles that of large junipers, but not quite as shaggy. English yew is toxic.
As a backdrop for more interesting plants, shiny xylosma, Xylosma congestum, may not get the respect that it deserves. If it seems to be a bit too common in some big landscapes, it is probably because it is so practical. It can function like the strictly shorn hedges that were popular decades earlier, but is a bit more adaptable to modern landscape styles. It can be formal or quite informal.
Formal hedges of shiny xylosma are typically no taller than eight feet, and a bit more plump than old fashioned privet hedges. They can get a bit sparse if kept too lean. Informal hedges are mostly lower and plumper, with casually irregular surfaces and no corners. Old shiny xylosma can grow as a small tree more than eight feet tall. Younger specimens are of the shorter cultivar, ‘Compacta’.
Established shiny xylosma is surprisingly resilient. Roots disperse impressive distances to reach moisture so that old specimens can survive without direct irrigation. Although, they prefer regular watering. Overgrown specimens can eventually regenerate nicely from coppicing or pollarding. The main disadvantage is that vigorous new growth will likely develop concealed but sharp thorns.
Victorian landscapes made good use of cherry laurel, Prunus laurocerasus. It works well as a large formal hedge. For more relaxed modern landscapes, it makes delightful informal screen. The main reason that it is now less popular than other hedging shrubbery is that it gets rather broad if not shorn back regularly. If allowed to grow as a low rounded tree, it can get twenty-five feet high!
Regularly shearing is not necessarily frequent. It should be efficient though. Confinement for such broad shrubbery is important. If shorn back farther than where the outer surface is desired late in winter, fresh new foliage can fluff out nicely within allowable space through spring. Subsequent aggressive shearing to maintain confinement may only be necessary once or twice during summer.
The big leaves are about three inches long, and luxuriantly glossy. If hedges get shorn less aggressively, but more frequently than two or three times annually, such big leaves can be rather shabby much of the time. If shorn less frequently, small trusses of creamy white flowers may get a chance to bloom. Cultivars are more compact than the species. One cultivar is variegated with pale gold.
Fences are necessary. They contain children, dogs and minor livestock. They exclude deer, cattle and others who are unwanted within an enclosed space. Some obscure unwanted scenery. However, even the more ornate sorts are more functional than aesthetically appealing.
That is why hedges are popularly grown to obscure fences that obscure outside scenery. Climbing vines take up less space than hedges, but are likely to damage the fences that they are intended to obscure.
Where I lived in town, the garden in back was surrounded by fences. I loathed them. I grew a grapevine on one. Another one was outfitted with a trellis of twine for pole beans to climb. Tall zonal geraniums obscured at least the lower half of the fence behind the laundry yard. I would have preferred no fences at all.
There were no children or dogs to contain. Nor were there cattle or deer to exclude. Except for the laundry and trash yards, there was no unwanted scenery to obscure. Nonetheless, the neighbors wanted fences, probably because they all believed that backyards should be fenced. It was just how it had always been.
Some urban fences are more like high and solidly constructed walls. Batons cover the seams between planks. Where local ordinance limits the height of fences, lattice is commonly added on top to (sort of) lawfully increase height. It is difficult to grow much on the shady north side of such tall fences.
I am fortunate that I do not work with many fences anymore. However, an area at work is surrounded by cyclone fences. It is necessary and practical, but would be very unappealing around landscape situations. I put pole beans on one, and two grape vines on another. If I must contend with them, I may as well take advantage of them.