Since the Dutch Elm Disease (DED) epidemic that killed so many old and stately American elm trees so many years ago, the old fashioned Chinese elm, Ulmus parvifolia, has been unavailable in nurseries. That is why there are only old and middle aged trees, and maybe a few feral seed grown trees. Chinese elm is not bothered much by the disease, but is a vector. ‘Drake’ is a modern DED resistant cultivar, but it has a very different personality, with a more upright and symmetrical structure.
The elegantly lanky trunk and main limbs can be quite curvacious, with distinctively blotched gray and tan bark. The deciduous foliage can be messy in autumn as it falls slowly and may linger through December. The neatly serrate leaves are only about an inch or two long, and half as wide. Mature trees can be more than fifty feet tall.
It was probably the extra chill this last winter that made some deciduous fruit trees bloom more profusely early in spring than they typically do. Unusually busy bees in some regions improved pollination and subsequent fruit set, although some was dislodged by late rain. The sudden warmth this last spring not only improved the flavor of fruit, but also made some grow larger than typical.
More and better fruit is usually what those who grow fruit strive for. The problem with some trees now is excess. After pruning our fruit trees every winter for a few years, we get to know how much to prune them to maximize productions without overloading the trees. When the trees produce more than expected, they may not be able to support the weight of their own fruit.
Many plum and peach trees have already dropped limbs that were overburdened with the weight of fruit. Nectarine, apricot, pluot (and aprium, plumcot and all those weird hybrids), and prune trees can potentially drop limbs as well. Even without breaking, heavy limbs can get disfigured simply by sagging downward. Broken or sagging limbs expose inner bark to sun scald.
Broken limbs obviously can not be salvaged, so can only be removed. They should be cut cleanly away without leaving stubs. Sagging limbs can be propped with notched stakes tucked under side branches that will keep them from sliding upward. The notches keep such stakes from sliding off to either side. Much of the excessive fruit can be removed from severely sagging limbs. However, if the fruit is so ripe that it will not be getting any heavier, there is no advantage to removal.
Formerly shaded bark that suddenly becomes exposed to direct sunlight should be shaded. If partly shaded though much of the day, it should be safe. If expected to be shaded next year by new growth, bark can be protected temporarily with duct tape or stapled cardboard, or even foliated bits of the limb that broke, tied over the bark. Light colored paint is unsightly, but can be applied to reflect sunlight from bark that is expected to remain exposed permanently.
Excessive weight is not only a problem for fruit trees. Some sweetgum, fruitless mulberry and old fashioned Chinese elm trees can produce so much healthy foliage that limbs hang lower than they should. Some shade trees can even drop limbs ‘very’ unexpectedly, when the weather is warm and humid, but without wind.
Japanese maples get all the notoriety. They have such delightful texture and form. Many are proportionate to small spaces, such as atriums. Realistically though, they are overrated and overused. Meanwhile, other maples that work as larger shade trees remain obscure. Norway maple, Acer platanoides, gets broad enough to shade much of an urban garden, but rarely gets to forty feet tall.
Of course, Norway maple has innate limitations. It dislikes arid and harshly warm desert climates. Nor does it like to be too close to the coast. Los Angeles is about as far south as it wants to live. In the Pacific Northwest, it gets much bigger, and develops greedy roots. The non-cultivar species is invasive there. Norway maple defoliates neatly for winter, but then refoliates late in about April.
Almost all local Norway maples are cultivars. ‘Schwedleri’ has richly bronzed foliage. It is rare now, but was a popular street tree in the 1950s. ‘Crimson King’ has richer purplish foliage, but is less vigorous. ‘Drummondii’ displays delightful variegation. The deciduous foliage of Norway maple turns soft brownish yellow or gold for autumn. The palmately lobed leaves may be five inches wide.
It is a hybrid. It is naturally occurring. Yet, most cultivars (garden varieties) resulted from intentional hybridization and selection. It is not as strange as it seems. Freeman maple, Acer X freemanii, is a naturally occurring hybrid of silver maple and red maple. It grows wild where the natural ranges of the parents overlap. From their example, breeders learned to selectively breed the cultivars.
These cultivars combine the fast growth rate of silver maple with the structural integrity of red maple. None get to be as imposing as the silver maple. Some get to be about forty feet tall and wide, which is a bit bigger than red maple gets in local climates. Foliage is lacy like that of silver maple, but more substantial, like that of red maple. It develops brilliant orange and red color for autumn.
Freeman maple, although locally uncommon, is one of the more practical maples here. Like silver maple, it does not require much chill in winter. Like red maple, it develops a symmetrical canopy with reasonably high branches. Roots should be complaisant with concrete. Because it is a hybrid, it is mostly sterile. It does not produce enough seed to be invasive in more conducive climates.
The best camphor trees, Cinnamomum camphora, are in parks and other spacious landscapes. Such trees have sufficient room for their broad canopies. Although they do not grow rapidly, they eventually get quite large, and perhaps too massive for confined urban gardens. Some of the older local trees are nearly fifty feet tall, and nearly as broad. They have potential to get much bigger.
Camphor trees excel as shade trees. Their light green or perhaps yellowish evergreen foliage is quite dense. Shade of groups of trees or large trees with low canopies inhibits the growth of lawn grass. Also, roots are likely to eventually elevate lawn or other features that are close to the trunks. Foliar canopies are billowy, but can be lopsided, especially in windy or partly shaded situations.
Trunks and main limbs of camphor trees are rather stout, and can be rather sculptural. Trees should be pruned for clearance while young. Otherwise, obtrusively low limbs can become prominent components of the canopies. The tan bark is distinctively checkered. It darkens handsomely with rain. All parts of camphor tree are quite aromatic. Frass from spring bloom can be slightly messy.
Modern urban home gardens are shadier and more confined than older suburban home gardens originally were. Modern homes are both taller and closer together on smaller parcels. Fences are also taller to compensate for the minimal proximity of adjacent homes. Less sunlight reaches the ground. There is not as much space available for shade trees. Nor is there as much use for them.
Huddled modern homes are simply not as exposed to sunlight as older suburban homes were. Sunlight is more of an asset than a liability. Walls, ceilings and windows are so thoroughly insulated that shade is less important. Solar arrays up on roofs must remain exposed to sunlight. Smaller and denser trees are more important for obscuring views of adjacent homes, rather than for shade.
Shade trees are still useful for rural and suburban homes. Shade helps to keep older and less energy efficient homes cooler through warmer summer weather. If strategically situated to the south, west or southwest, they shade homes during the warmest time of day. Well proportioned trees do not darken too much of their gardens. Deciduous trees allow warming sunlight in through winter.
The popularity of modern urban homes is directly proportionate to the popularity of small evergreen trees. Such trees fit into smaller garden spaces, and permanently obscure unwanted scenery. Big deciduous shade trees that are practical for larger garden spaces become obtrusive in confined spaces. Defoliation in winter reveals unwanted views, and deprives the landscape of privacy.
Some of the more practical of small evergreen trees are actually large shrubbery. English laurel, Carolina cherry, photinia, hopseed bush and various pittosporums can get high enough to obscure neighboring windows. All are conducive to pruning if they get too tall. If staked on single straight trunks, or pruned to expose a few sculptural trunks, they do not occupy much space at ground level.
Tristania laurina, and some melaleucas are naturally small to midsized evergreen shade trees. Some species of Podocarpus can be pruned as midsized trees.
There are several oaks, especially natives, that do not need much more water than they get from rain. Pin oak, Quercus palustris, is not one of them. It is naturally endemic to areas that are damp or swampy for part of the year. It is more tolerant than others are to lawn irrigation, but is also more sensitive to drought.
Compared to other oaks, pin oak grows fast while young. It can get two stories tall in about ten years. Then, it takes more than twice as long to double in size. Old trees do not get much more than fifty feet tall, with trunks nearly three feet wide.
The deciduous foliage turns as brown as a grocery bag in autumn, and may linger late into winter, or until it gets replaced by new foliage in spring. The distinctively deeply lobed leaves are about two to five inches long, and about two thirds as wide. Each leaf has five or seven lobes. Each lobe has five to seven teeth.
There really is no such thing as a perfect tree. Some are not quite as messy as others. Some have better structural integrity than others. Some have gentle roots; and some stay proportionate to tight spots. However, without exception, all trees grow, drop leaves, and disperse roots.
This is an important consideration when selecting any tree, and especially when selecting a street tree for the narrow space between the curb and the sidewalk (which is commonly known as a park strip). Even where there is no sidewalk, or where the sidewalk is at the curb, most of the obstacles are the same.
Street trees should have reasonably complaisant roots that should not be likely to damage curbs, sidewalks or roadways, at least for several years. They should naturally develop reasonably high branches. They will need to be pruned higher than trucks that may park at the curb. Street trees must also tolerate harsh exposure.
Wider park strips can of course accommodate larger trees. Those that are only two feet wide or narrower are probably not wide enough for any tree larger than photinia, purple-leaf plum or English hawthorn, which are difficult to prune for clearance over roadways and sidewalks.
Messy leaves, flowers or fruit that might not be a problem within the garden might be more of a problem at the curb. It is not so easy to rake such debris if cars park over it. Trees that are commonly infested with scale or aphid are likely to drop sticky honeydew (scale and aphid poop) onto parked cars.
Unfortunately, those who get street trees do not always get to select them. Many municipalities assign specific trees to specific streets. Some streets have a few trees to choose from. Others have only one option. Home Owners’ Associations (HOAs) decide if and where new trees get planted.
Crape myrtle is probably the most common choice for a new street tree because the roots do not get big enough to damage pavement. However, the canopies are not very big either. They stay too low to be pruned above trucks. Crape myrtle is susceptible to scale infestation that can get bad enough to make sidewalks sticky.
For many years, London plane (sycamore) had been another popular street tree. Unfortunately, the voracious roots can damage pavement within only a few years. The messy foliage discolors and starts to fall before autumn.
Deciduous trees that were bare all winter are now foliating and making shade. They sure will be appreciated when the weather gets warmer through summer. They will defoliate next autumn, in time to let warming sunlight through while winter is cool. Their lifestyles are naturally compatible with those of the people who live with them. They really have the system down.
Evergreen trees are good at what they do as well. They obscure unwanted views and provide privacy all year. If given adequate space and located far enough away from the home and neighboring homes, their shade should not be a problem. Like any other feature in the landscape, properly selected and strategically placed evergreens are quite functional.
There are certainly more to evergreen trees than the coniferous (cone-bearing) evergreens like pine, spruce, cypress, cedar and juniper. Any tree that retains foliage throughout the year is evergreen, including camphor, Southern magnolia, carob, California pepper, coast live oak, fern pine, all palms and all eucalypti, just to name a few. There are really too many to list.
Larger modern homes on smaller parcels are a bit more challenging to evergreen trees than more traditional homes that have more space around them. Average fences do not maintain privacy for upstairs windows that are too close to neighboring homes. However, there is less space and sunlight for trees, and additional shade can be a bother for lower windows.
It seems that smaller trees are often the best fit for bigger homes. Sometimes, a large evergreen shrub, like one of the various pittosporums, can do the job of an evergreen tree, but fits better where space is limited. As silly and passe as they seem to be, Italian cypress are narrow enough to fit into tight spots, at least until they get too big.
Contrary to popular belief, most evergreen trees are messier than most deciduous trees. They drop only minor volumes of foliage, but they do so throughout the year. Deciduous plants drop most or all of their foliage within a limited time about autumn. Only those that drop flowers, fruit or both in spring and summer are messier than evergreens.
One might surmise that a tree that is resilient enough to be the state tree of Texas is not too discriminating. If it can take the heat and humidity of the Lone Star State, it can make it anywhere! However, pecan, Carya illinoinensis, actually prefers heat and humidity, and is bored with the mild local climate. The nuts and the mess that comes with them are actually less abundant than they would be in the Gulf Coast States. The deciduous foliage is not quite so colorful in autumn.
A mature pecan tree may stay a low as fifty feet, or get twice as tall. The height is usually nearly double the width. Generous watering can cause roots to buttress and displace nearby pavement. Most local pecan trees that are intentionally planted are garden varieties that were bred for bigger pecan nuts. Seed grown trees tend to produce nuts that are nearly comparable to the nuts they were grown from. The pinnately compound leaves have nine or more leaflets that are about two or three inches long.