Arborvitaes are quite uncommon here. Korean arborvitae, Thuja koraiensis, is one of the more uncommon among them. It is therefore uncommonly uncommon, or even rare. Not many examples are observable within local landscapes. Yet, some compact cultivars are becoming more available from nurseries. It will likely become more popular in the future.
Korean arborvitae is a large evergreen shrub or small tree. In the wild, it grows as tall as thirty feet, and half as broad. ‘Glauca’ has bluish foliage and grows only about fifteen feet tall, and ten feet wide. ‘Glauca Prostrata’ gets only three feet tall, and about six feet wide. Flat foliar sprays with clasping scale leaves resemble those of more familiar arborvitaes.
Also like more familiar arborvitaes, Korean arborvitae appreciates regular watering. It is resilient to brief lapses of irrigation once established, though. It tolerates partial shade as well. Although it prefers sandy loam, Korean arborvitae adapts to most soil types. Soil of inferior quality is rarely a problem. Spider mites can possibly infest during warm weather.
Initially after planting, many new trees and some large shrubs rely on stakes for stability. Some limber trees also need temporary structural support for thin trunks. Staking is only necessary until confined roots disperse and young trunks mature. Then, trees and large shrubbery stand on their own. Stakes help with the transition from nursery to landscape.
Different trees require different types of stakes. Palm trees need none at all. Spruce trees are likewise stout enough to stand alone. Camphor trees, though, typically need staking both for structural integrity and stability. Landscape stakes provide stability while nursery stakes provide trunk integrity. For most trees, landscape stakes displace nursery stakes.
Landscape stakes are those that loosely support new trees within their new landscapes. Nursery stakes, if present, are those that direct straight trunk growth in nurseries. Binding to nursery stakes inhibits trunk expansion, though. Therefore, it is better to remove them as soon as possible. This should occur after planting and staking with landscape stakes.
Landscape stakes, for adequate stability, should extend below roots of associated trees. This puts them into the solid undisturbed soil below the excavated soil. Also, they should be about as high as the lowest branches of their associated trees. For shrubbery and low branched trees, they should be about five feet high. Stakes are in standardized lengths.
One stake is adequate for some small trees. Other larger trees may justify two. Likewise, one top strap for each stake may be adequate. Secondary straps about halfway between top straps and the ground might be useful. They minimize bowing of limber trunks. Short nails can hold straps in place. Straps should cross over between their stakes and trees.
Staking should be as unobtrusive as possible. If it supports trees too rigidly, it can inhibit trunk growth and development. Trunks that are able to move somewhat with breezes will be stronger. If binding remains necessary, it should be as loose as possible. It constricts as trunks expand. Ultimately, as trees mature, staking and binding become unnecessary, and should be removed.
Old fashioned photinias, which are now rare, are thorny and messy with copious berries. Almost all modern photinia, though, are Fraser’s photinia, Photinia X fraseri. It is a hybrid that is both thornless and fruitless. It is also among the most popular plants for evergreen hedges and screens. Therefore, it is readily available from nurseries and garden centers.
After shearing, Fraser’s photinia develops richly reddish bronze new foliage. Such color eventually fades to dark green. However, the process repeats after each shearing, which may be three times annually. Shearing also enhances foliar density, and refines hedges. Bronze color is best in spring, after late winter shearing. It fades slightly faster in summer.
Without shearing, Fraser’s photinia can become a small tree as tall as fifteen feet. Foliar color is less vivid, though, and only develops once for spring. Also, unshorn trees bloom, often profusely, with big trusses of tiny white flowers. Some find the floral fragrance to be objectionable. Compact or variegated cultivars of photinia may sometimes be available.
Motorized hedge shears are the most overused home garden power tools. They are very useful for hedges and similarly shorn shrubbery. The problem is that they too often shear vegetation that needs different types of pruning. Also, they often perform proper shearing at improper times. The efficiency is a distraction from seasonality and proper horticulture.
Dormant pruning happens during winter while subjects are most dormant. It is the proper technique for deciduous fruit trees, roses and many deciduous species. However, winter may not be the best time to prune certain evergreen species. Dormancy may not be such an advantage for them. It limits the ability to outgrow the evidence of pruning or shearing.
For example, an English laurel hedge appears quite tattered immediately after shearing. As it resumes growth at this time of year, it recovers very efficiently. Therefore, it does not appear to be tattered for very long. However, recovery would have been quite slow while growth was slower during winter. Autumn and winter are not good times for such pruning.
Actually, this is a good time to prune or shear all sorts of evergreen hedges. Pittosporum, privet, xylosma and boxwood all recover efficiently from such techniques. They will likely need pruning again, and perhaps a few times, through summer. Then, their growth slows sometime during autumn. Hopefully, they will not need pruning until the following spring.
Some evergreen shrubbery blooms for spring, though. Premature pruning would deprive them of such bloom. Laurustinus is likely already finished blooming, so may be ready for pruning now. Lemon bottlebrush, though, blooms somewhat later. If possible, its pruning should occur after its primary late spring bloom. It will hopefully not grow too big by then.
Photinia is now generating appealingly coppery red new foliage. Pruning would remove much of such foliage, so should be a bit later if possible. Then, shearing as foliage turns green would promote another phase of red new foliage. Of course, photinia trees are too large for such shearing. Also, trees bloom more than regularly pruned hedges or shrubs. Some find the floral fragrance of photinia bloom to be objectionable.
Winter bloom may or may not be an benefit of laurustinus, Viburnum tinus. Most grow as regularly shorn hedges that are unable to bloom much between shearing. Those that do bloom often generate a floral fragrance that some find to be objectionable. Nonetheless, with only timely pruning, laurustinus does bloom for winter. Many consider this an asset.
Flowers are small and white or blushed with pink. They huddle together in dense cymes, which are about two or three inches wide. Their dense evergreen foliage is forest green. Individual leaves are paired, about two or three inches long, and half as wide. They have a very slightly raspy surface texture. Mature laurustinus can sucker from their basal roots.
If bloom is not a concern, laurustinus can be a dense shorn hedge, only several feet tall. Otherwise, it can become a dense small tree more than twenty feet tall and ten feet wide. Once established, it does not need much water and can actually survive with just rainfall. It is not very discriminating about soil quality. Mites or mildew can become problematic in damp coastal climates, particularly among shaded or very congested specimens.
Although it classifies as a tree, mugo pine, Pinus mugo, is more like shrubbery. Old trees may be only a few feet tall, and maybe twice as wide. Not many are more than eight feet tall. Their form is densely rounded. Foliage is deep forest green. Stiff paired needles are only about one to two inches long. Plump cones are not much longer, and are quite rare.
Mugo pine, although native to the Alps, is a traditional feature of Japanese gardens. Yet, it is rare within other types of gardens. It does not grow fast or big enough to be practical for much more than aesthetic appeal. It does excel at that, though, by developing such a distinctly rounded form. It can work well as foundation planting or a short informal hedge.
Mugo pine is not particularly discriminating about local soils or climates. It merely craves sunny and warm exposure. Mature specimens do not need much water, but are healthier with occasional irrigation. Mugo pine appreciates room for unrestricted growth. Shearing deprives it of its natural form and texture. If necessary, selective pruning may be tedious.
Its silly name is actually justifiable. The papery fruits of Hopbush, Dodonea viscosa, can be useful as a substitute for hops. Almost all hopbush are female, so produce such fruits. However, bloom and subsequent fruit production is variable. Vigorous plants are likely to produce less fruit. Also, some specimens might become male, and therefore be fruitless.
Hopbush is most popular as an informal evergreen hedge. It also works well as a formal hedge. With selective pruning, it can become a small tree with shaggy bark on sculptural trunks. It develops a narrowly upright form while young, but may eventually grow ten feet wide. It grows about twice as tall. Overgrown specimens are quite conducive to pruning.
Hopbush exhibits a uniformly fine foliar texture. Individual leaves are two or three inches long, but narrow. Foliar color is soft bronzy green. ‘Purpurea’ is more purplish bronze, but is not quite as vigorous. Roots are very complaisant, but do not disperse well if irrigation is too generous. Established hopbush is undemanding, so does not require much water. It tolerates soil of inferior quality too.
Sawara false cypress cultivars do not develop into real trees.
Just like other types of false cypress, the Sawara false cypress, Chamaecyparis pisifera, naturally gets much larger than its many cultivars that are sometime grown in gardens for their colorful and interestingly textured foliage. Although not large trees, they can get nearly thirty feet tall in wild groves in Japan. Most garden varieties stay less than ten feet tall, and some stay much shorter.
‘Cyano-Viridis’ (‘Boulevard’), with feathery blue green foliage, is one of the more popular cultivars. It grows slowly to more than six feet tall and broad. ‘Filifera’ has very different foliage, with tightly fitting scale leaves on limber cord shaped branches. It stays a bit shorter but can get a bit broader. ‘Mops’ is similar to ‘Filifera’, but stays about a foot and a half tall and broad. ‘Filifera Aurea’ and ‘Golden Mops’ are just like ‘Filfera’ and ‘Mops’, but with yellow foliage.
Reflected glare or harsh exposures can burn foliage. Full sun is not a problem, unless enhanced by glare from surrounding pavement or lightly colored walls. Partial shade is not a problem either, but compromises foliar color, particularly yellow.
Shearing or major pruning deprives false cypress of their naturally appealing forms and textures. They should therefore get plenty of space for their mature size, and get trimmed lightly for shape only when necessary.
Many dwarf plants are very practical. The many different dwarf cultivars (cultivated varieties) of false cypress that are grown for their interesting forms, textures and foliar colors are much more proportionate to home gardens than similar specie in the wild, which are big enough to get harvested for timber. Oranges are easier to reach on dwarf trees than on standard trees, which get as big as shade trees.
However, not all plants should be bred to be dwarfs. Dwarf Southern magnolias certainly have their appeal for tight spots, but do not make as much shade as larger trees do. Compact cultivars of crape myrtles (although not actually dwarfs) take too much time to grow above truck traffic to be practical as street trees.
Many classic annuals and perennials are likewise bred to be too compact to be as practical as they were in the past. Annie of Annie’s Annuals in Richmond refers to this all too common practice as ‘boinkification’. It makes many blooming plants more marketable and resilient to shipping and installation, but deprives them of their natural form and elegance.
Short annuals and perennials certainly have their place. Lobelia, sweet alyssum, dwarf marigolds and petunias are fine along walkways and in pots with other larger plants. They also work well as bedding plants for a profusion of color. Yet, there is all too often too much of a good thing. Some flower beds are simply so big and plain, that it would be just as colorful to paint an area orange instead of planting so many marigolds.
Taller flowering annuals like nicotiana (flowering tobacco), cosmos and zinnias add depth behind lower growing annuals. Dahlias are perennials that can accomplish the same thing. Some of the older and less common varieties of familiar bedding plants that have not been so boinkified also work well. There are even petunias that can get two feet tall and wide! These taller plants also provide cut flowers; which is something that boinky plants are not so good at.
Boinkification also compromises fragrance and aroma. Bedding dianthus have almost no fragrance at all; unlike the old fashioned dianthus and carnations that had such distinctive spicy fragrance. Modern zonal geraniums are more colorful than classic varieties, but their foliage is not quite as aromatic.
Not only does increased foliar density of boinky plants promote the proliferation of many diseases and pests; but the genetic violations necessary for boinkification interfere with resistance to diseases and pests!
Meriwether Lewis of the Lewis and Clark Expedition encountered the western native mock orange, Philadelphus lewisii, in 1806, and gave it his own name. It inhabits an extensive range that reaches from the northern Sierra Nevada to southern British Columbia to western Montana, but is somewhat sporadic within its natural range. It is the state flower of Idaho, and is commonly planted in state, national and even some county parks within its range and throughout the rest of California.
Partial shade is not a problem for mock orange, but full sun exposure promotes more abundant bloom. The simple, strikingly white flowers that bloom in spring are less than two inches wide with only four petals. However, their remarkably rich orange fragrance is unexpectedly powerful. The two inch long, forest green, deciduous leaves on arching limber stems are a nice backdrop. ‘Goose Creek’ has double flowers.
Because regular pruning or shearing of outer growth inhibits bloom and compromises natural form, mock orange is best where it has plenty of space to grow wild, or at least where the upper canopy can spread out naturally if the lower canopy gets pruned away to form a small tree with multiple trunks. After bloom, older deteriorating stems can be pruned out, to favor newer stems emerging from the base. Overgrown plants can be cut to the ground in winter, and will regenerate over the following summer to bloom in the second spring. Mature mock orange gets nearly ten feet tall and broad.
Tony Tomeo 