Pittosporum eugenioides

Pittosporum eugenioides leaves have distinctively wavy margins.

Large shorn hedges or informal screens are the more popular functions of Pittosporum eugenioides. It works like a modern and more relaxed option to privet. What few garden enthusiasts know is that it can alternatively be allowed grow into a small tree, either as a standard (on a single trunk) or with multiple trunks. It grows rather efficiently to more than twenty feet tall and about half as broad while young, and as it matures, can eventually get about thirty feet tall and broad.

The glossy leaves have appealingly wavy margins and distinctively pale midribs. The slightly fragrant flowers are only pale yellow, and are not abundant among young trees. Big old trees often bloom enough in autumn to be pleasantly fragrant. Stems and foliage are lemony fragrant when pruned or shorn. However, the common name of ‘lemonwood’ (or tarata) is not so common locally for Pittosporum eugenioides.

Hopbush

Hopbush makes a nice small tree.

Johnny jump up and jumping cholla have no more than amusing names in common with hopbush, Dodonea viscosa. Neither a dangerous cactus nor a docile annual, hopbush is an elegantly upright and evergreen shrub. It is very popular for both informal and formally shorn hedging. With pruning, it can become a small tree with handsomely furrowed bark.

Hopbush has potential to get about as tall as a two story house, particularly with pruning for tree form. Conversely, with only occasional pruning for hedge form, it is just as happy to stay just six feet tall. Trees with single and straight trunks fit nicely into narrow spaces. Trees with a few irregular trunks that lean outwardly are more sculptural for larger areas.

The narrow evergreen leaves are about two or three inches long, with light bronzy color. ‘Purpurea’ has purplish bronze color, but does not grow as vigorously. Most hopbush are female, and generate interestingly papery seed. Bloom and seed production are variable though, and some specimens become male. Roots should be complaisant with concrete.

Shearing Can Not Fix Everything

Shearing enhances foliar density without bloom.

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.

Horridculture – Fences

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This is not exactly visually appealing.

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.

Lineup

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The usual suspects.

There is significant traffic right outside. It is one of the three busiest roads around. No one here really minds, because we are mostly too busy with something else while we are here. We are accustomed to it as part of the ‘scenery’. The noise sometimes makes it necessary to shout to each other, or take a telephone call somewhere else, but is not too much of a bother otherwise.

However, the scenery that those in the traffic see from the road might be slightly less than appealing. Industrial buildings surrounded by pavement, building materials, work vehicles and all sorts of associated items are all that are in here. Next door, there is a herd of dumpsters! It is a view worth obscuring. Bay trees and box elders that used to screen the view are too tall now.

I should have planted these five Arizona cypress in a row along the road last autumn. If I were to plant them now, I will need to water them occasionally until next autumn, not that I would mind. After their first winter, they would be happy on their own. They would start to obscure the view within only a few years, and unlike box elders, would stay evergreen through winter.

They really should have been planted a long time ago. They have been in the same cans for so long that the medium within has decomposed and collapsed. Without staking, their lean trunks became disfigured in confinement. They really would not have needed to be staked if they had been planted sooner and been able to grow more vigorously. Fortunately, they should recover.

A Monterey cypress will be planted at the low end of the row next Saturday, even if these Arizona cypress are not planted until autumn. I will explain later.

Karo

91211Of all the popular pittosporums in Western landscapes nowadays, the karo, Pittosporum crassifolium, is certainly not one of the most familiar. It might have been one of the earliest to have been popularized here though. Because of its resiliency to coastal climates, it was a common hedge in San Francisco during the Victorian Period. With minimal watering, it did well farther inland too.

Karo are nice fluffy evergreen shrubs that can get fifteen feet tall. They excel both as informal screens and refined hedges, and can be staked as small trees on single straight trunks. Alternatively, lower growth of big shrubby specimens can be pruned up to expose a few delightfully sculptural trunks. ‘Compactum’ is a densely foliated mounding cultivar that might stay less than three feet tall.

The Latin name, Pittosporum crassifolium, is quite descriptive. The literal translation is “sticky-seed thick-leaf”. The two or three inch long leaves are not really thick, but their slightly grayish upper surfaces and more grayish tomentous (fuzzy) undersides make them seem almost succulent. Small and round seed pods eventually split open to reveal dark seed glued together with sticky resin.

Pittosporum tobira

90925A surplus of common names seems to be a common theme for many plants that we thought we knew the names of. The simple Pittosporum tobira, which might be known here by its Latin name, might instead be known as mock orange, Australian laurel, Japanese pittosporum, and Japanese cheesewood. Its native range is about as diverse, including Greece, Japan, Korea and China.

Back in the 1990s, the compact cultivar known as ‘Wheeler’s Dwarf’ was common enough to be as cliché as tam junipers were in the 1950s. There are actually a few other dwarf and variegated cultivars that do not share that reputation. Most are low, dense and mounding. ‘Variegata’, although not a compact dwarf, grows slower and stays smaller than the unvariegated straight species.

Otherwise, Pittosporum tobira gets about ten feet tall and wide. It can eventually get significantly taller, especially if lower growth is pruned away to expose the sculptural trunks within. If shorn as a hedge, it should not be shorn so frequently that the dense foliage is always tattered. Leaves are delightfully glossy and convex. Small trusses of modest pale white flowers are sometimes fragrant.

Waxleaf Privet

90918Here on the West Coast, privets had traditionally functioned like hollies had in the East. They are conducive to shearing into the big formal hedges that were popular during the Victorian period. Since then, as gardening space became more limited, the common glossy privet became less popular than the more compact and complaisant waxleaf privet, Ligustrum japonicum ‘Texanum’.

Since it does not get much higher than ten feet, and typically stays less than eight feet tall, waxleaf privet is proportionate to urban gardening. As a formal hedge, it can be shorn to stay less than two feet from front to back, although taller hedges look better if allowed to get bulkier. As an unshorn informal screen, it should not get much broader than six feet, with an appealingly billowy form.

Foliage is evergreen and remarkably glossy, sort of like that of holly, but without the prickles. Regularly shorn hedges should not bloom, but might produce a few trusses of tiny white flowers inside of the shorn surfaces. In sunny situations, unshorn glossy privet blooms profusely enough to be mildly fragrant in spring. Bloom sometimes produces floppy clusters of tiny but messy black berries.

Hedges – Living In The Background

90918thumbPretty soon, as autumn weather starts to get cooler, some deciduous plants will develop brilliant color before defoliating for their winter dormancy. Throughout the rest of the year, evergreen plants with gold, silver, bronze, bluish, purplish, reddish or variegated foliage are more colorful than common green foliage is. A few deciduous plants with colored foliage turn different colors in autumn.

Such colorful foliage is generally appealing in the garden. However, there are reasons why not all plants in the garden are so colorful. There really is the potential for too much of a good thing. If all foliage was always colorful, landscapes would look cluttered. Flowers would not be so prominent. There are many situations for which plain and simple evergreen foliage is likely the best choice.

That is why simple evergreen hedges of the various species and cultivars of pittosporum, privet, holly, arborvitae and laurel are still so popular. Some are formally shorn. Where space is sufficient, others are informal screens in which the shrubbery is more or less allowed to assume its natural form and size. The various boxwoods are useful for smaller evergreen and formally shorn hedges.

Most contiguous hedges and screens are intended to separate spaces or obscure fences or buildings. Some sporadic sorts might only expected to disrupt the expansiveness of large buildings or partially deflect prevalent breezes. What they have in common, is that they are in the background. Some are behind or next to lawns, patios or decks. Others are behind more prominent plants.

Shearing hedges that are adjacent to lawns, patios and decks is of course much easier than shearing those that are behind other plants. Screens or hedges behind rose gardens, dahlias, flower beds, or anything that might be damaged by the process of shearing a hedge, should be of the sort that do not need to be shorn regularly. Nor should they be so colorful that they steal the show.

If possible, maintenance of hedges should be scheduled to coincide with the off season of plants in their foreground.

Fake Six on Saturday

P90824K‘Six on Saturday’ is a weekly tradition for many of us who enjoy sharing six horticulturally oriented pictures on Saturday. I just did it earlier this morning.

This is not ‘Six on Saturday’. It is just one picture of six arborvitae. What’s worse is that there is an indistinguishable seventh at the far end of the row. It blends into the sixth in this picture. There are seven barberry between them, with the seventh beyond the last arborvitae. This picture was taken more than a week ago, so most of the amaryllis are done blooming now.

This row of arborvitae and barberry was installed early last winter, after a grungy hedge of photinia was removed. It would have been nice to salvage the photinia, but they were such a mess that the process would have taken more than two years, and even then, would have been patchy.

These arborvitaes will not grow into a contiguous hedge like the photinia were, but already soften the otherwise uninviting visual impact of the plain and uniform fence behind. They will grow taller and broader, but will never get so big that they will be difficult to maintain. It should be easy enough to get behind them to prune away parts that get too close to the fence.

I happen to be pleased that we were able to incorporate this sort of formality into an otherwise completely informal landscape. The irregularity of the terrain, as well as the randomness of the big forest trees that were here before landscapes were installed, make such formality nearly impossible. Even if it were easier, formality is not exactly fashionable in landscape design.

Despite their imposed formality and exotic origins, both the arborvitae and the barberry are remarkably compatible with the native flora of the surrounding forest landscape.