Dutch elm disease became a serious problem for American elms in the 1930s. However, it did not reach California until half a century or so later. Chinese elm, Ulmus parvifolia, is not very susceptible to the disease, but is a vector. In other words, it can survive infection to share it with other species of elm. Consequently, it became unavailable by the 1980s.
Some mature specimens of formerly common Chinese elm still inhabit older landscapes. Younger specimens in newer landscapes are mostly ‘Drake’ Chinese elm. They are a bit more upright, with more symmetrical form. More importantly, they are not vectors of Dutch elm disease. Other cultivars that are also resistant are rarely available at local nurseries.
Classic and formerly common Chinese elm can eventually grow more than fifty feet high. Some can grow thirty feet wide to shade an entire urban front lawn. Some cultivars might grow nearly as high, but are generally not quite as broad. Their blotchy gray and tan bark adorns curvaceous limbs. Their small deciduous leaves are not very colorful for autumn. They can be copious, messy and quite tedious to rake.
Appropriately, this picture was taken on Halloween. The ‘DEAD END’ sign and cemetery beyond, which are visible to the lower left of the picture, were also coincidental. The several headless redwood trees are the primary topic. Obviously, they were decapitated because of the electrical cables above. Otherwise, redwoods with such healthily plump trunks would be rather tall by now. After all, coastal redwoods are the tallest trees in the World. Unfortunately for them and those who are now appalled by their disfigurement, reliable and safe electrical service is more of a priority than poorly situated trees. It is no fault of the trees. Nor should this atrocity be blamed on those who executed it. Their only better option would be complete removal of the subjects, and perhaps replacement with smaller trees that will not grow tall enough to get too close to the electrical cables above. Maintenance of clearance of the vigorously upright redwoods from the cables above is a chronic problem that must be morally challenging for the arborist who must perform the necessary procedures. However, removal of several such significant trees would be very objectionable to the Community, which is very likely why these trees remain, regardless of their severe and irreparable disfigurement. Application for permits for their removal requires posting of such intentions on the trunks of the subject trees, to which neighbors would very likely protest. None of this would be such a problem now if only trees that are more appropriate to this particular situation were installed instead! Did the landscape designer who designed this landscape even visit the site during the design process, or was it all done on paper in a remote studio? Why did those who installed these trees not foresee this problem and modify the landscape plan and species selection accordingly?
No other coniferous tree develops such distinctively irregular form. Very few exhibit such distinctively steely grayish blue foliar color. Blue Atlas cedar, Cedrus atlantica ‘Glauca’ is no simple shade tree. It is a striking trophy tree that is worthy of prominent display within grand landscapes. It is ideal for traffic circles, without other trees to obscure its boldness.
Blue Atlas cedar is also sufficiently resilient for traffic circles and other difficult situations. Arid warmth, even if enhanced by pavement, roofs or walls, should be no problem. Once established, blue Atlas cedar does not crave much irrigation. It should be able to survive with none. Excessively frequent or copious irrigation is more likely to become a problem.
Blue Atlas cedar can grow a hundred feet tall in the wild within its native range. It should not grow much more than half as tall with good exposure within landscapes. Trunks may slowly grow to almost six feet wide. Canopies can eventually grow wider than thirty feet. ‘Glauca Pendula’ is weeping blue Atlas cedar, which is smaller but even more exquisite. ‘Aurea’ with gold tips, is very rare.
This is what taking sides looks like. The right side was taken completely off, leaving only the left. The view from the other side would show that the left side was taken completely off, leaving only the right. It is not such a good picture because it is difficult to distinguish the extent of the damage from what is going on in the background. Realistically though, a better picture would be even worse, since the extent of the damage would be more obvious. The justification for such damage here is more obvious, since, obviously, this is a bad situation, with no room for balanced growth. Although survival is possible, this is not what nature intended. Natural growth should be an asset, and efficiently directed to where it can be useful, which would most likely be much more balanced than this. Incidentally, this is a coastal redwood, which is the Official State Tree of California. This sort of pruning would be just as damaging to Western hemlock, Douglas fir or blue spruce. For that matter, it would be just as damaging to longleaf pine, Western white pine or Ponderosa pine. Ultimately, it is bad technique for any tree in any situation.
Japanese maples became so popular for their novelty that they are no longer novel. The diversity of their many cultivars is their primary appeal now. Vine maple, Acer circinatum, lacks such diversity, but is actually more novel. It is native from Mendocino County to the southwestern corner of British Columbia. Yet, it is very rarely available at nurseries here.
Vine maple has not been in cultivation for nearly as long as Japanese maple has. This is why its diversity is limited to not much more than a dozen cultivars. Its cultivars are even rarer than the simple species. Only a few ever become available, and almost exclusively by online purchase. Consequently, with very few exceptions, they are initially very small.
Vine maple grows somewhat like Japanese maple, typically with a few sculptural trunks. With regular pruning, it can stay as short as ten feet. It rarely grows more than twenty feet tall. The lobes of its palmate leaves are wider than those of Japanese maple. Leaves are only about three inches long and wide. Foliage develops bright orange color for autumn.
The taller trees are typically the first to admit that summer is finished and that it is now autumn. Perhaps because they are higher up and into the changing weather more than smaller plants that are sheltered and closer to the ground. Some trees are changing color nicely. Others are thinking about it. Evergreens are, . . . well, evergreen; so they may not seem to change so much. Nonetheless, autumn is here, and most plants will consequently be going dormant for the winter, or at least slowing down a bit.
For many trees and other plants that need to be pruned, the next few months will be the best time for it. Because they are more or less dormant, they are not very aware of whatever procedures they are subjected to. When they wake up in spring, they simply adapt to the earlier pruning and start growing as if not much happened to them. Dormancy is like a natural anesthesia for trees and plants.
Conversely, the end of winter and beginning of spring is the worst time to prune many trees and plants because they are just emerging from dormancy, so are wide awake! If necessary, minor pruning done properly is generally tolerable, but should realistically be done either before or after that time. Maples, birches, mulberries and figs express their disapproval of late pruning by bleeding profusely, and sometimes for a long time.
Deciduous trees are most dormant by winter when their leaves have fallen off. Pruning them a bit earlier would probably be harmless, but deprives them of their colorful foliage. Maples, gingkoes, poplars and mulberries typically defoliate earliest. Oaks, elms and sweetgums (liquidambars) take their time, holding onto their leaves until they get knocked out by wind and rain. Oaks and elms are not very colorful anyway. Sweetgums though can look too good to get pruned late into winter!
Arborists are physicians of trees, so can prescribe recommended pruning and maintenance procedures. Many trees, like Chinese elms, fruitless mulberries and willows, need more attention than others. Austrian black pines and Eastern redbuds are not so needy. Blue spruces that are allowed to remain branched to the ground and have enough space around them may never need a visit by an arborist.
Regardless of how much attention any particular tree needs, when it develops a problem that is out of reach, it should be assessed by an arborist, and hopefully pruned accordingly. Because trees are the most substantial features of the landscape, and can develop worse problems if not maintained properly, it is imperative to procure the services of qualified arborists; and not trust such important tasks to a gardener or anyone who can find a chain saw and pick up. Fortunately, certified arborists can be found at the website of the International Society of Arboriculture (ISA), at www.isaarbor.com.
Not every garden can accommodate coastal redwood, Sequoia sempervirens. Wild trees can grow hundreds of feet tall, with trunks as wide as thirty feet! None are so big in home gardens, but only because they are still young. They can live for more than two thousand years. By that time, those in urban landscapes are very likely to become major concerns.
Realistically though, urban trees are generally more compact than wild trees. There is no need for extreme height without competition from other similarly tall trees. Besides, lower trees are less vulnerable to wind. Warm and dry wind can desiccate foliage. Strong wind can dislodge branches. Limbs that fall from very high canopies are extremely hazardous.
Almost all modern coastal redwoods from nurseries are of the cultivar ‘Soquel’. They are strictly conical and symmetrical in form, with uniform foliation. ‘Aptos Blue’ exhibits more relaxed form and very slightly bluish foliage. ‘Santa Cruz’ should be more available than it is since it is more resilient to arid warmth. Old seed grow trees are genetically variable. For old formal gardens, they are less formal than younger trees.
Banana trees, much like palms, arboriform yuccas and cordylines, are herbaceous trees. They develop no secondary xylem, or wood. What seems to be trunks are pseudostems, which are just leaves in very tight bundles. These pseudostems grow from subterranean corms, which can grow rather big. Each pseudostem is monocarpic, so dies after bloom.
Although they are very easy to grow, banana trees are not very popular. They can be too easy to grow, and become overwhelming. In some climates, frost can ruin their foliage for part of the year. In some exposures, their foliage can get shabby from wind. Some expect generous and frequent applications of fertilizer. All want generous and frequent irrigation.
These characteristics are contrary to growing banana trees merely for appealing foliage. Realistically, that is what most are for. Those of the Ensente genus are fortunately easier to maintain, but fruitless. Their lushly huge leaves are spectacular, relatively durable and generate much less debris. However, after a few years, they die without generating pups.
Banana trees of the Musa genus generate fruit, although some are primarily ornamental. A few produce delightfully colorful fruit that is too small, seedy or starchy to be palatable. Musa are more pervasive although less popular than Ensente. While Ensente come and go, Musa are reliably perennial. Several produce enough pups to potentially be invasive.
Musa, unlike Ensente, therefore develops colonies of a few to many pseudostem trunks. A few new trunks can replace each old trunk faster than they can deteriorate after bloom. Removal of deteriorating old trunks promotes growth and fruiting of new trunks. So does culling of congested new trunks. They propagate very easily by division with intact roots.
Because banana trees are tropical, they are unfamiliar with the seasons here. They grow fast with warmth but very slowly without it. They bloom randomly though. Flowers that try to bloom during autumn may stagnate long enough to rot through winter. Late fruit can do the same. Fruit that begins to develop early is much more likely to finish prior to autumn. Some cultivars develop faster.
Sequoia sempervirens, coastal redwood is the Official State Tree of California, and the tallest species of tree in the World. One large specimen can contain more lumber than many acres of Douglas fir (really). While some trees ensnare kites, redwoods collect satellites. Redwood lumber can be delivered anywhere in western North America simply by aiming a tree in the direction of delivery while cutting it down. Redwood shadows reach Japan at dawn and New England at dusk. The moon is covered with craters because it could not dodge the growing redwoods while orbiting over California. You can see for yourself how tall redwoods are just by looking in this direction from wherever you are in the World. Unfortunately though, not all of the debris that falls from the huge canopies of redwoods burns up in the atmosphere on its way down. Such huge canopies generate a lot of debris. Almost all of it is finely textured foliar debris. Some is twiggy detritus. The worst of it are significant branches. The descent of most of such branches is slowed by lower branches and foliage that they encounter on their way down. However, the lowest branches of some canopies are very high up, and falling branches resume acceleration after falling past them. Also, some falling branches fall outside of their canopies. Even branches that weigh only a few pounds can be extremely dangerous. Many falling branches weigh many pounds, and some are as big as trees. The fallen branch in the picture above is only several feet long and about three inches wide, (and happened to fall through the only three inch wide plank in a pedestrian bridge. The replacement plank needed to be custom cut.) I am annoyed by this relatively minor damage, but also relieved that it was not worse.
Dwarf Alberta spruce is more like a strictly conical shrub than a small tree.
Unlike other related white spruce, which get more than fifty feet tall, dwarf Alberta spruce, Picea glauca albertiana ‘Conica’, stays smaller than its Latin name, rarely getting more than seven feet tall. It is so dense and conical that it should never need to be pruned. Shearing only damages its short light green to grayish green needles. Dwarf Alberta spruce is compact enough to live in large tubs or urns, as long as its sensitive roots are well insulated. (Concrete or wooden planters are well insulated, so do not transfer too much heat to the roots within. Ivy or ground cover cascading over and shading planters also helps.) Foliage should be sheltered from harsh exposure, since it can be desiccated by warm breezes or reflected glare, like from large windows or light colored south facing walls.
Tony Tomeo 