It may not look like much, but it gets annoying, especially at night.
The industrial shop buildings at work are not exactly visually appealing. Fortunately, they are partially obscured from the roads outside by wild forest trees within the adjacent Zayante Creek and a roadside ditch. One road is on the opposite side of Zayante Creek. The other is on the opposite side of the roadside ditch that is perpendicular to Zayante Creek. Their intersection with associated traffic signals is therefore right outside. I added five Arizona cypress trees to the forested area of the roadside ditch, and three Monterey cypress to the forested area of Zayante Creek, to obscure the buildings more in the future. Unfortunately, though, some of the trees beyond needed to be removed for renovations of a major water main for Santa Cruz. One was a mature Monterey cypress between one of the shop buildings and the intersection of the two roads outside. Not only did this reveal the view of the backside of the building from the roads and intersection, but it revealed the view of the intersection from the few windows of the building. Now, from where I do much of my writing, I can see this traffic signal monotonously change from green to yellow to red.
Redwoods grow much too tall for this particular application.
The worst part of getting stuck in traffic on the West Valley Freeway was actually not that I was without a Buick. It was the objectionable view of ridiculously dysfunctional landscaping that flanks newer section of the freeway south of Steven’s Creek Boulevard. After more than a decade and a half, it should be performing much better than it does.
Instead, it has developed far more problems than the older section to the north. Many of the purple leaf plums have been overwhelmed by their own green suckers. Some of the flowering pears also have serious suckers, or have been damaged by the harsh exposure they get on the side of a freeway. All sorts of plants have succumbed to irrigation problems.
The overly abundant micro-trees like purple leaf plums and crape myrtles are not proportionate to a freeway landscape. London planes will eventually be more proportionate, but are almost as useless for muffling the sound of traffic while they are bare through winter. The few functional features of the landscape are can only be seen in the background.
Meanwhile on the relatively old fashioned Junipero Serra Freeway, the landscape does what it was intended to do when it was planned in the late 1960’s. Where there is enough space, mature eucalyptus trees absorb ambient noise all year. Arizona cypress trees do the same where there is less space. Western redbuds and oleanders add a bit of color whether they get watered or not.
Home gardening may not always get the sort of planning that freeway landscapes need, but deserves the same sort of common sense. Much of what goes into the garden will be around for a very long time, so should be selected accordingly in order to function as intended with as few problems as possible. Yet, it is sometimes worth taking minor risks to get trees and plants that get the job done.
For example, crape myrtles have become much too common because they do not get big enough to cause many problems. They are used as street trees because they will not damage pavement; but they do not get big enough to make much shade or to get out of the way of trucks. Honey locusts may not seem like such a good choice because they may eventually displace pavement when they get older, particularly if watered too much while young; but they are more proportionate and out of the way.
Proper selection of plants simply makes the garden work better. Trendy plants like crape myrtles, London planes, carpet roses and dwarf Heavenly bamboos (nandinas) certainly work well in the right situations, but are not necessarily the best choices for every situation. Desired function, proportion (when mature), exposure, potential problems, maintenance requirements and landscape style are just some of the variables that should be considered when selecting new plants for the garden.
Classification of this species may be complicated. About five distinct varieties of Arizona cypress, Cupressus arizonica, occur naturally. Some may sometimes classify as distinct species. Some grow no higher than twenty feet, with stout and shrubby form. Some grow fifty feet high, with sculpturally irregular form. Botanists may not agree on their identities.
Old trees that mostly grew from seed are typically noticeably variable. Some exhibit nice bluish green foliar color. Others are more grayish green. Modern trees are mostly modern cultivars with strikingly uniform silvery blue foliar color. Some are supposedly conducive to hedging, which enhances foliar color. Although evergreen, foliage is freshest in spring.
Without hedging, Arizona cypress develops splendid natural forms. Whether sculpturally irregular or compactly shrubby, it may need only minor grooming. Its finely textured foliar debris disappears into any ground cover below. However, such foliage can have a mildly herbicidal effect on lawns. Arizona cypress trees in a row can be an effective windbreak.
Staking is not quite the same as binding with stakes. It is more for the benefit of the roots than the trunks, which is what binding is for. Staking should support new trees only while such trees disperse roots for adequate stability. As trees do so, stakes become obsolete. Actually, stakes that remain for too long may be detrimental to healthy tree development.
Binding with stakes promotes straight trunk growth. It is particularly practical for trees that naturally develop crooked or multiple trunks. It is a technique that is quite common within nurseries, although not home gardens. However, many trees retain binding stakes when they arrive from nurseries. For a while after planting, some continue to benefit from them.
However, binding may be more detrimental than staking if it remains for too long. Trunks that become reliant on any sort of supportive stake remain weak or limber. Also, tape that binds trunks to stakes can become constrictive as trunks grow. It is important to remove it before it begins to interfere with trunk expansion. Looser tape can be useful if necessary.
For example, California pepper tree naturally develops a few irregular and limber trunks. To produce trees with single and straight trunks, nurserymen bind single trunks to stakes. They then prune out other trunks and low limbs until main trunks attain an optimal height. Because they are still limber, trees remain bound to their stakes while available for sale.
However, such stakes provide only support for trunks. They do nothing for stability while trees disperse roots into their new gardens. Additional staking with heftier stakes may be necessary for that. Such stakes must extend into undisturbed soil below the roots of such new trees. If possible, it is better to merely replace binding stakes with supportive stakes.
The next best option is to replace tape that binds young trunks to stakes with looser tape. This maintains the straight form of such trunks without inhibiting their growth. Supportive stakes, in addition to binding stakes, maintain their upright posture. Most trees need only supportive stakes, realistically. A few trees, especially new palms, need no stakes at all.
Where it grows wild in the eastern half of North America, honey locust, Gleditsia triacanthos, may not seem like it would be such an appealing shade tree. It is too thorny and messy to make many friends. As it matures and grows nearly seventy feet tall and half as broad, the thorny stems stay overhead and out of the way. However, a larger canopy makes more messy and sometimes unsightly foot long seed pods.
Modern cultivars of the thornless form Gleditsia triacanthos inermis are friendlier and not so messy. Mature trees only grow about half as tall as wild trees. Their main problem is their buttressing roots, which can displace pavement, but stay tolerably low for lawns. Honey locust is actually a good shade tree for lawns (if minor buttressing is not a problem) because it makes just enough shade without getting too dark for a lawn or other shade tolerant plants below. Pods are rare.
The big eight inch long leaves are bipinnately compound, which means that each leaf is divided into smaller leaflets, which are also divided into even smaller leaflets that are about half an inch long. Although individual leaves are actually quite large, the collective foliage is pleasantly delicate and lacy. This foliage turns yellow early in autumn and disintegrates as it falls, leaving minimal debris to rake. New foliage develops somewhat late in spring, along with inconspicuous flowers.
Trees are the most substantial components of a landscape.
Shady characters inhabit some of the best gardens. Actually, most of the best gardens have some sort of shade tree. There are so many to choose from for every sort of garden. Some stay small and compact enough to provide only a minimal shadow for a small atrium. Others are large enough to shade large areas of lawn.
Like every other plant in the garden, shade trees should be selected according to their appropriateness to particular applications. Favorite trees are of course welcome, but should be placed in appropriate locations where they will be less likely to cause problems later. For example, those of us who like silver maples should only plant them where they will not crowd other trees, and if there is sufficient area to accommodate them when mature. Southern magnolias are bold shade trees, but create too much mess for infrequently raked lawns, and create too much shade for many other plants around them.
Shade trees near to the home should be deciduous if possible. This means that they will drop their leaves to be not so shady when it would be good to get more sunlight through winter. Honey locust, red oak, Raywood ash, tulip tree and many varieties of maple (except Japanese maple) are some of the best. Silver maple gets a bit too large for small gardens, but is an elegant shade tree for large lawns. Japanese maple and smoke tree are small trees that fit nicely into an atrium or a small enclosed garden.
Evergreen trees also make good shade trees, but should be kept farther from the home if possible, in order to avoid shading too much through winter. Besides, most evergreen trees are messier than deciduous trees so are not so desirable over lawns, patios or roofs. Camphor tree and several of the well behaved eucalypti are delightful shade trees where their litter will not bother anyone. Mayten tree is a smaller tree for more confined areas. Strategically placed evergreen shade trees can also function to obscure unwanted views.
Every shade tree creates a specific flavor of shade. Honey locust makes just enough shade for summer weather without making the garden too dark for other plants and lawn grass. Silver maple is a bit shadier. The shade of redwood and Southern magnolia (when mature) though, is so dark that not many other plants want to get close to them.
Remember that appropriate shade trees may be in the garden for decades or even centuries. It is best to select them accordingly so there will be fewer problems in the future.
Within home gardens, Douglas fir, Pseudotsuga menziesii is very rare. So is the bigcone Douglas fir, Pseudotsuga macrocarpa of Southern California. However, they are not rare in the wild. Sometimes, suburban or rural home gardens develop around them. They can be awkward to accommodate. They are magnificent trees, but simply grow much too big.
Contrary to its rarity among home gardens, Douglas fir is actually common within homes. after all, most houses are constructed mostly of Douglas fir lumber. Most Christmas trees here are plantation grown Douglas fir. It is a major lumber plantation commodity in Chile, Argentina, New Zealand and Europe. Douglas fir is the Official State Tree of Oregon too.
Douglas fir is a grand tree in the wild. Old trees can grow more than two hundred feet tall with trunks eight feet wide! Their limbs may extend more than thirty feet from their trunks. It is obviously disproportionate for home gardens. Its soft evergreen foliage is delightfully aromatic, though. Its flattened, two-ranked needles are less than an inch and a half long. The female cones exhibit uniquely lacy scales.
Soil saturation is detrimental to trees for a few reasons. Excessive irrigation is almost as problematic, even without saturation. Chronic excessive moisture compromises stability by inhibiting deep root dispersion. Instead, it promotes shallower root buttressing. It may compromise structural integrity, too. It is generally the cause of spontaneous limb failure.
Spontaneous limb failure is exactly what it implies. Its spontaneity is what makes it more hazardous than limb failure caused by wind. It happens while the weather is calm, warm and perhaps humid, when least expected. Limbs might sag and produce cracking noises immediately prior to falling. However, they quite often fall suddenly and without warning.
Spontaneous limb failure is associated more with gravity than wind. It occurs as vigorous stems literally grow faster than they can support. Warm weather accelerates foliar growth that increases weight. A lack of wind and perhaps enhanced humidity inhibit evaporation from foliar surfaces. Inhibition of evapotranspiration limits weight loss during weight gain.
Deciduous trees are generally more susceptible to spontaneous limb failure. Sweetgum, willows, poplars and elms are particularly vulnerable. A few evergreen trees are likewise susceptible, though. They include coast live oak, Monterey cypress and a few eucalypti. Fruit trees exhibit spontaneous limb failure if they can not support the weight of their fruit.
The potential for spontaneous limb failure is rarely obvious. Limbs of some types of trees may visually appear to be too heavy or floppy. Limbs of Monterey pine, for example, may lean to one side if they sag prior to failure. However, valley oak, carob and sycamore are notorious for concealing their weaknesses. Even arborists can not predict all limb failure.
Wild trees within new landscapes are particularly vulnerable to spontaneous limb failure. They are not accustomed to irrigation through otherwise arid summers. Some can adapt as landscapes with irrigation develop around them. Others overindulge and become too heavy for their own trunks or limbs to support. New trees adapt to irrigation as they grow.
Apricot trees, which are mostly of the species Prunus armeniaca, have history here. Vast apricot orchards formerly inhabited the Santa Clara Valley. Many remain as a significant industry of the San Joaquin Valley. Apricot trees are both famously reliable and famously productive here. If they can not inhabit orchards, they can be as happy in home gardens.
Home garden apricot trees are not quite the same as orchard trees. Most are grafted onto dwarfing rootstock to stay more compact than orchard trees. More cultivars are popular in home gardens than in orchards. Regardless, even relatively compact home garden trees need dormant pruning in winter. Otherwise, they provide more fruit than they can support.
Apricot trees change with the seasons. They are strikingly bare while dormant for winter. Their profuse white bloom is spectacular for early spring. Their rich green foliage mostly obscures their fruit as it ripens through early summer. It then turns cheery yellow before it defoliates in autumn. Home garden trees should be about ten feet tall with good pruning. Fruit is difficult to reach in overgrown trees.
Those who know trees mostly agree that the more traditional catalpa, Catalpa speciosa, from the Midwest is the best catalpa, with soft leaves between half and a full foot long. In late spring or early summer, impressive upright trusses suspend an abundance of bright white, tubular flowers with yellow or tan stripes and spots at their centers. Individual flowers are as wide as two inches. Mature trees can be taller than forty feet and nearly as broad.
From the Southeast, Catalpa bignonioides, is a bit more proportionate to urban gardens though, since it only gets about seventy five percent as large, with leaves that are not much more than half as long. The flowers are also smaller, and not quite as bright white, but are more abundant than those of Catalpa speciosa are. The stripes and spots at their centers are slightly more colorful purplish brown and darker yellow.
Both catalpas can be messy as their flowers fall after bloom. Fortunately, the big leaves are easy to rake when they fall in autumn. Long seed capsules that look like big beans linger on bare trees through winter.
Catalpa speciosa is almost never seen in modern landscapes, and not exactly common even in older Victorian landscapes around downtown San Jose. A few remarkable specimens remain as street trees in older neighborhoods of Oakland, Burlingame and Palo Alto. Most young trees were not planted, but instead grew from seed from older trees that are now gone.
Catalpa bignonioides is actually quite rare locally. A few old but healthy specimens can be seen around downtown Felton, with a few younger trees that grew from seed around the edges of town. Trees in Golden Gate Park in San Francisco are not as happy because of cool and breezy summers and mild winters.
Tony Tomeo 