Autumn Simply Will Not Wait

40917thumbReady or not, it will be autumn in just a few days. Formal hedges can be shorn one last time if they need it. They will not grow much until spring. Actually, photinia and the various pittosporums should not be shorn much later than now if they exhibit any dieback. Some of the diseases that cause dieback are more likely to infest freshly cut stems during rainy weather. Citrus and plants that can be sensitive to frost should not be pruned later, since pruning can stimulate new growth that will be more sensitive.

For the same reason, most plants should not need fertilizer as their growth naturally slows. Through winter, new growth is likely to be damaged by wind or discolored by nutrient deficiency. Even if the nutrients that keep foliage green prior to autumn are in the soil, some are less soluble at cooler temperatures. It is really best to allow plants to get some rest. Only plants that are active through winter, like cool season vegetables, cool season annuals, and some cool season turf, will benefit from fertilizer.

However, some plants that are generally dormant through cool winter weather will not be completely inactive. Many plants, particularly tough evergreen perennials like lily-of-the-Nile, African iris and many ferns, continue to disperse their roots to be ready to sustain new foliar growth next spring. This is one of the reasons why autumn is the best time to get such plants into the garden, even if they do not seem to do much until spring. Autumn is also a good time to seed lawns or install sod.

The other reason for planting in autumn is that, as the weather gets cooler and rainy, new plants that have not yet dispersed their roots will be less likely to dry out than they would be in spring or summer. Some bulbs that will soon be available in nurseries want to be in the garden before winter because a bit of cold weather promotes healthier bloom.

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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 clich√© 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.

Barberry

60817It may not look too nasty, but barberry, Berberis thunbergii, is the sort of small hedge that one goes through only once. It does not have big strong branches to hold anyone back. In fact, the limber branches are quite twiggy. The tiny spines are not impressive either, and might go unnoticed by cursory observation. Yet, they are sharp enough and plentiful enough to make quite an impression!

Because it is so unpleasant to prune, barberry should probably be planted where it has room to grow as big as it wants to without bothering anyone. If it is too close to walkways, it will either offend whomever bumps into it, or whomever needs to prune it to keep it out of the way. Mature plants will unfortunately need to be pruned eventually, so that old deteriorating stems can be groomed out.

The most popular cultivars of barberry have dark reddish or purplish foliage. A few are variegated with white; and a few have golden foliage. Green barberries are now uncommon. The tiny leaves turn bright orange in autumn before winter defoliation. Densely dwarf cultivars may not get much taller than two feet. Taller cultivars might get taller than six feet. Some barberries are very vertical.

Vines Do Not Replace Hedges

90619thumbUrban homes are innately close to other urban homes. Newer homes are even closer to each other than older homes are, and are more imposing. Establishing or maintaining privacy can be a challenge, especially for high windows in narrow spaces. Even though home builders prefer to place windows strategically, some windows invariably face into neighboring windows or gardens.

Trellised vines are a popular but rarely effective remedy to this dilemma. The narrow spaces between houses and below the eaves can be dark enough to inhibit growth. Consequently, vines are typically sparse or bunched on top of their trellises. Their most vigorous growth is often awkwardly long shoots trying to find a way out of the shade. Vines are not exactly easy to work with anyway.

There are of course exceptions. With regular maintenance, some finely textured vines that are reasonably tolerant of shade can be effective for downstairs windows. (Upstairs windows are out of reach.) If shorn very regularly, English ivy on lattice works almost like a hedge. (Ivy does not fill in on more open trellises.) Trellised star jasmine is even better, but needs more depth (front to back).

Yet, with few exceptions, big evergreen shrubs or small evergreen trees that tolerate shade are more practical. They support their own weight, so only need to be pruned for confinement and clearance from the houses that they provide privacy for. Some shrubs and trees should be pruned to stay at the desired height, so that superfluous upper growth does not shade out lower growth.

The various podocarpus are some of the better small trees for narrow spaces between houses because they are are somewhat tolerant to shade, and are so easily pruned into shape. Some of the taller and more upright pittosporums work nicely in sunnier spots. Arborvitae tolerates more shade, and naturally stays narrower. Since some of these better options might grow slowly, they can be planted with faster growing shrubbery that can be pruned back, and eventually removed as the preferred plants mature.90619

Photinia

60316As 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 fifteen 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.

Bullwinkle II

P90303What makes this Bullwinkle worse than most is that I pruned it like this myself. What makes it worse than worse is that it did not need to be pruned in this disfiguring manner for clearance from utility cables like the last one I wrote about was. https://tonytomeo.com/2018/08/08/horridculture-bullwinkle/ It is instead an attempt to renovate an overgrown hedge that was behaving something like a fat hedge. https://tonytomeo.com/2018/06/06/horridculture-fat-hedges/

In fact, the only reason it did not qualify as a fat hedge is that it had plenty of space for all of its superfluous bulk The side to the left was only beginning to encroach into the driveway on that side, and was easily pruned back to the curb, which for now, is adequate confinement. The side on the right was only beginning to encroach into the upstairs balconies, and was likewise easily pruned back for reasonable clearance.

The problems with this hedge were within and on top. It had been shorn back only for minimal confinement for so long that all the foliage on the sides was within a thin external layer. Pruning any farther back would have exposed a thicket of necrotic stems in various degrees of deterioration that had been accumulating within the interior for many years. Almost all growth was directed to and concentrated on top, which shaded the interior and lower stems even more than the accumulation of necrotic crud within did. Since the top had always been pruned down to the same height, all subsequent growth after pruning on top was above where it had been pruned previously, which was of course above the height where it was wanted, and consequently removed when the hedge was pruned again. There was no incentive for lower foliage to develop.

The hedge is there to obscure the view of a building on the left from the windows of the building on the right. The most important foliage for that purpose is the lower foliage, which is precisely what is lacking. Almost all resources were going to the upper foliage, which was contributing nothing, while shading out the lower growth. Although the inner thicket of necrotic stems was partially helping to obscure the unwanted view, it was also inhibiting healthier lower growth.

The illustration shows what remains after the useless top and necrotic interior were removed. After the picture was taken, the left and right sides of the hedge were pruned lower to eliminate the useless upper foliage that was not contributing to the function of the hedge. As unsightly as it is, it partially obscures the view of the building on the left from the building on the right, and will obscure it more as new foliage develops. Now that the interior is exposed, new growth should develop within the interior, and lower to the ground. Because the area is partially shaded by nearby redwoods, the exposed interior limbs are not likely to be damaged by sun scald.

After the new interior growth is established and obscuring the view, the external sides that are there now can be pruned back farther and sloped inward toward the top so that the lower growth of the hedge gets more sunlight. The hedge certainly does not need to be as wide as it is. It would be easier to maintain if it were narrower and so close to the allowable boundaries. Ultimately, with appropriate pruning over the next few years, this old hedge should be restored.

‘Little Ollie’ Olive

60302Those of us who appreciate olive trees for their fruit production or distinctively gnarly trunks probably would not understand the popularity of the Little Ollie olive, Olea europaea ‘Little Ollie’. Not only is is completely fruitless, but it lacks sculptural trunks and limbs. It is instead a short and and shrubby plant that gets only about three or four feet tall, with very dense grayish green foliage. Only the narrow evergreen leaves are recognizable as those of an olive tree.

Little Ollie olive behaves something like boxwood, and does not grow much faster. It can even be shorn as a hedge or topiary. It is quite resilient to heat and harsh exposure, and once established, it does not need much water. Because it is so compact, and has such resilient roots, it is popularly grown in large urns or planters. The grayish foliage is a nice backdrop for more colorful annuals and flowering perennials.

English Boxwood

90306While flashier but typically weaker modern cultivars of so many other specie are being developed, the most popular of the many cultivars of English boxwood, Buxus sempervirens, remain the same. There is not much to improve on. Most cultivars get only a few feet tall, and are densely foliated with inch long evergreen leaves that are excellent for topiary and low formally shorn hedges.

One of the difficulties with formal hedges, or any formal application, is replacement of any specimens that die. There are not very many of the different cultivars available locally; but it can be quite difficult to distinguish between some of them. One specimen of the wrong cultivar ruins conformity! Another concern is that the aroma of the foliage when disturbed may be objectionable to some.

In the wild, English boxwood grows as small trees or rather larger shrubs with relatively open structure. Locally, such specimens are only very rarely found in old Victorian landscapes, such as at the Winchester House. ‘Suffruticosa’ is so compact that it popularly allowed to grow as as unshorn and nearly spherical shrubs. ‘Argenteo-Variegata’, ‘Variegata’ and ‘Marginata’ are variegated.