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Roots Prefer To Roam Freely

Some yuccas are unhappy in pots.

Roots are innately mysterious. They consume much of the resources that plants require. They stabilize the stems above them. Few plants can survive without them. Yet, roots are very secretive about their work. Almost all are invisibly subterranean. Consequently, they get minimal consideration. A lack of consideration is a root cause of many root problems. 

Every plant species has distinct environmental preferences. Some plants require full sun exposure. Others tolerate or prefer partial shade. Some are more discerning than others. Similarly, plants that naturally disperse their roots extensively dislike confinement of their root systems. Small plants and some riparian plants are more adaptable to confinement.

Annual bedding plants and many small perennials perform well within pots, planters and small spaces because they do not need to disperse their roots extensively. Some woody plants with fibrous root systems, such as azalea, boxwood and andromeda, can adapt to confinement also. Occasional pruning can keep them proportionate to their root volumes. 

Most of the popular succulents perform remarkably well in confinement. Some types that disperse their roots extensively if necessary will adapt to confinement by dispersing their roots only as far as they must. If they get all they need within a pot, they need not go any farther. However, succulents that are endemic to dry desert regions are not as adaptable. 

Desert plants can survive warm and dry summers because they disperse their roots very extensively. They can not do so within the confinement of pots and planters. This should not be a problem that systematic irrigation can not compensate for. Unfortunately though, these same plants are too susceptible to rot if their roots are damp during warm weather.

So, some plants that are the most resilient in the ground are the least resilient in pots. Of course, this is not an absolute rule. Yuccas from tropical and temperate climates perform well either in the ground or in pots. Those from desert climates are likely to rot in pots. In general, drought tolerance and container gardening are two fads that are not compatible. 

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Foliage Can Provide Color Too

There is considerable variety in variegation.

Flowers get all the credit for color. They certainly are the most colorful features in the garden, as well as the most fragrant. However, foliage can do so much more than simply provide green. It can be hued with yellow, red, blue, purple, bronze, gray, or variegated with white or yellow. Plants with colorful foliage can range in size and function from small annuals and perennials to shrubbery, vines and even trees.

Hydrangea, hosta, ivy, English holly and various pittosporum are some of the more popular plants for white variegation, and are often variegated with yellow. Euonymus can conversely be variegated with white, but is usually variegated with yellow. New Zealand flax can be variegated with pink, bronze, brown or gold. Box elder is a good sized deciduous tree that can be variegated with white, or alternatively frosted uniformly with gold as new foliage emerges in spring. There is even a variety that has slightly purplish or smoky colored new foliage.

Silver mountain gum, silver Mediterranean fan palm, lamb’s ears, artemesia and the various dusty millers have remarkably silvery foliage. Silver mountain gum can grow into a mid-sized tree with a stout trunk. Lamb’s ears is a low perennial. Olive trees, some junipers and the various lavenders have gray foliage. Colorado blue spruce and some agaves have striking blue color.

Various purple leaf plums and Japanese maples are famous for their purplish foliage. Smoke tree and some beech have even darker purplish foliage. Some New Zealand flax and cannas can be just as purple or comparably bronze.

Actually, New Zealand flax and cannas, as well as junipers known for blue or gray foliage, can alternatively be bright yellow. Golden arborvitae, golden honeylocust and golden Monterey cypress really stand out nicely against darker green.

Colorful foliage tends to be most colorful as it develops freshly in spring, and tends to fade somewhat through summer. Gold junipers can actually fade to basic green by autumn. Shade inhibits most types of coloration, but can show off variegation better. There really is so much variety with colorful foliage that it is impossible to generalize.

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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.

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There Are Rules To Hedging

Few plants are conducive to shearing

All the wrong plants get shorn. Mow, blow and go gardeners are known for shearing everything that they can reach into creepy and unnaturally geometric shapes, usually flared out at the top, and bulging obtrusively into otherwise usable space. Yet, functional formally shorn hedges are passe and almost never shorn properly.

First of all, a formal hedge should be uniform, which means that all the plants that comprise it should be the same, and planted at the same distance from each other. Any plants within a formal hedge that die should be replaced with the same plant. A single English boxwood plant added to a Japanese boxwood hedge will always stand out with a different shade of green and growth pattern. Seedlings of other plants that grow up into a hedge should be removed before they become part of it.

Secondly, a formal hedge should be contained within defined boundaries. It should get neither too tall, nor too deep (from front to back). A fat hedge wastes space. There is no excuse for a hedge to encroach obtrusively over walkways, driveways or patios.

The vertical faces of a hedge should be completely vertical or slope very slightly inward at the top, but should certainly not slope outward to shade lower growth. A slight inward slope is more important on a northern face of plants that are sensitive to shade.

Hand pruning hedges (with hand shears) produces the best finish, but takes quite a bit of time for big hedges. Shearing with typical hedge shears cuts leaves as well as stems, so can cause foliage with large leaves to look a bit tattered for a while. Hedges that grow fast may need to be shorn twice or more annually. Some hedges can get shorn back aggressively once annually, and then allowed to fluff out evenly through the rest of the year. Bottlebrush and escallonia hedges can bloom nicely and evenly if shorn only once annually.

Glossy and wax leaf privet are among the most traditional of formal hedges. Glossy privet can get quite tall, but wax leaf privet actually has glossier foliage. Photinia and shiny xylosma have a bit more color, but want a bit more space (from front to back). Boxwoods make very nice small hedges. Pittosporums are available in various shapes and sizes. Pittosporum eugenioides gets quite tall, and can be kept quite lean. Pittosporum tobira is shorter and wider.

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Sunlight Is Becoming A Commodity

Sunlight has not changed. Architecture did.

Shade trees are no longer appreciated like they had been. Only half a century ago, they were important components of suburban landscapes. Big deciduous trees shaded broad lawns and sprawling roofs during the warmth of summer. They defoliated to let warming sunlight through during winter. Now, modern architecture would not accommodate them.

Sunlight has not changed. Human interaction with it has. Modern homes are significantly taller, so create bigger shadows. They are closer together, with less garden space that is not within their bigger shadows, or shadows of adjacent homes. Higher fences intended to compensate for the minimal proximity of adjacent homes contribute even more shade.

Gardening can be difficult within the limited space and abundant shade of modern home gardens. Small evergreen trees or big shrubs that obscure unwanted scenery above the fences can also obscure much of the sunlight that manages to get past the infrastructure. Substantial vegetation in neighboring gardens can get close enough to be influential too. 

The primary part of modern homes that is not excessively shaded is the roof, which is not used for gardening. Trees that are proportionate to modern home gardens are not much taller than associated modern roofs. Modern attics are fortunately insulated so efficiently that shade is not important. Besides, many modern homes are outfitted with solar panels. 

Walls and windows of modern homes are efficiently insulated as well. Warming sunlight during winter is therefore not as much of an advantage as it is for older homes, although it is appealing within sunnier homes. Ironically, the utility cables of many modern homes are subterranean, so will not interfere with trees that get too big for their confined spaces. 

Regardless of their functions within their landscapes, even small trees can develop roots that are sufficiently aggressive to displace pavement and deck suspensions, particularly since they are likely to be close to them where space is limited. Turf grass that is thin and wimpy because of insufficient sunlight is more susceptible to lumpiness of surface roots. Because of proximity, neighboring gardens must be considered too.

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Fragrant Flowers Often Lack Color

Unremarkable flowers can be remarkably fragrant.

It is presumptuous to believe that all the fancy breeding that is done to enhance the characteristics of flowers necessarily ‘improves’ them. Breeding only makes flowers more appealing to those who enjoy them in their gardens. Most flowers were already quite efficient for their intended function in their respective natural habitats long before humans started tampering with them. As far as flowers are concerned, they only need to get pollinated.

Some flowers use flashy color or patterns to be visually attractive to pollinators. Others use fragrance to be olfactorily appealing. Small but profuse flowers that are neither colorful nor fragrant have given up on insect or animal pollinators, so instead rely on the wind to disperse their pollen.

Not many flowers are both remarkably colorful and remarkably fragrant like freesia, lilac and wisteria were earlier in spring. Lily and bearded iris are of course very colorful, but not all types are fragrant. The big and bold flowers of cereus cactus, moon flower and angel’s trumpet are only fragrant because they bloom at night, and rely on nocturnal  pollinators who benefit from a bit more guidance in the dark.

Many fragrant flowers are somewhat showy, like gardenia, star jasmine, pink jasmine and honeysuckle. (However, gardenia are almost never healthy and showy locally.) Many of the most reliably fragrant flowers are really not much to brag about. Pittosporum tobira, Pittosporum undulatum and sweet osmanthus are known more for the appealing evergreen foliage than for their small and nondescript flowers. The flowers of sweet osmanthus may actually be difficult to find amongst the obscuring foliage. Night blooming jasmine is sometimes planted around corners or in the background because even the foliage is not too appealing, although the powerful candy-like fragrance is a favorite for warm evenings.

Fragrant flowers can be annuals like sweet alyssum, bulbs like hyacinth, or perennials like tuberose. Woody plants with fragrant flowers can be vines like stephanotis, shrubs like mock orange (Philadelphus spp.), or trees like Southern magnolia. Some have brief bloom seasons, while others bloom for quite a while.

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Layer To Propagate Favorite Plants

Ivy takes root as it grows.

Ivy is creepy. It creeps everywhere. As it does so, it extends roots into or onto whatever it creeps over. Not only does it do this to climb, but it also does this to propagate. It literally roots as it goes, to function more as a swarm of countless small plants instead of a single big plant. A bit of well rooted stem may grow independently from the original as a ‘layer’.

Many vines do the same, even if they are normally climbing vines that just happen to fall onto the ground. A few shrubs and trees, especially riparian sorts, are happy to do it also if lower limbs lay onto damp soil. Such a rooted stem is known as a layer because it lays on the ground to root. In a home garden, a layer might root below a layer of mulch or soil. 

In fact, many plants in home gardens are easy to propagate by intentional layering. Many develop roots more reliably if layered than if propagated from cuttings. They grow almost like cuttings, but while attached to the original plants to sustain them. Layering produces only one or a few new plants, unlike cuttings, but for most home gardens, that is enough.

Some plants are easier to layer than others. Pines and most eucalypti are uncooperative to the technique. Rhododendrons, azaleas and camellias layer relatively easily, but may take more than a year to finish. Elms and magnolias are even happier to layer, but rarely retain low stems. Some plants layer best after spring bloom. Others layer through winter.

An intentionally layered stem should be partially buried, with a few inches of stem below the soil, and a few inches of the tip of the stem protruding above the soil. Notching about a third of the way through the underside and applying rooting hormone promotes rooting. Regular watering is necessary through the process, which continues at least until winter. 

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Make Copies Of Favorite Plants

Honeysuckle can layer naturally, and will most certainly layer if a portion of stem is simply buried or weighed down under a rock.

Where they grow wild in riparian environments, box elders, willows and cottonwoods are not as clumsy as they seem to be. As the rivers and creeks that they live so close to erode the soil around them, they often become destabilized and fall. Yet, this is actually part of their plan. If their original roots remain somewhat intact, the limbs and trunks develop new roots where they touch the ground. Eventually, these rooted limbs and trunks develop into new and separate trees.

In home gardens, a similar technique known as ‘layering’ can be employed to propagate one or a few copies of many other plants. Many sprawling vines and ground covers, such as ivy, honeysuckle, blue rug juniper and trailing rosemary, are likely to develop roots where their stems touch the ground anyway. Rooted stems need only to be found, dug and separated as new plants. Shrubbier plants need a bit more help.

Azalea, rhododendron, camellia, holly and just about any plant that has low stems that can be bent downward into the soil can be propagated by layering. Redwood, elm and magnolia do not always have limbs that reach the ground, but any that do would be pleased to cooperate as well. In fact, there are only a few woody plants that do not develop roots by layering, such as some pines and most eucalypti.

A layered stem only needs to be partly buried to develop roots. The tip should protrude from the soil a few inches. A short stem may barely protrude above the soil. A layered stem of a plant that develops adventitious roots very efficiently can be as long as a few feet. A very flexible stem can easily be held down by the weight of the soil that it gets buried with. A more rigid stem may need to be held down with a rock.

Before getting buried, the stem should be cut about a third of the way through to promote development of roots. The cut should be made on the underside so that it stays open when bend downward and buried. A bit or rooting hormone powder applied to the open wound accelerates the process. It works almost like taking a cutting, but without completely separating the cutting from the parent plant right away.

Once buried, a layered stem should be watered regularly until it gets dug while dormant (or mostly dormant) the following winter. By that time, the rooted stem can be dug and pruned from the parent plant, and then planted where desired. Because it takes a few months for enough roots to develop, layering should be done in spring.

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Limb Failure Of Spontaneous Nature

Riparian trees notoriously shed limbs spontaneously.

Winter storms sometimes break limbs or topple trees. Such damage is no surprise during winter because that is when almost all windy weather happens here. Early storms during autumn might be more damaging because deciduous trees are less aerodynamic prior to defoliation. Nonetheless, falling trees and limb failure are typically associated with wind.

That is why spontaneous limb failure is such a surprise when it happens, typically during pleasantly mild or warm weather of spring or early summer. It is more likely without wind than with it. Humidity, although atypical here, is a contributing factor. Healthy trees within riparian situations or lawns are more susceptible than distressed trees in drier situations. 

Particular types of trees are more susceptible to spontaneous limb failure as well. Valley oak, coast live oak, sweetgum, carob, some pines and various eucalypti may shed limbs after an unusually rainy winter or an increase of irrigation. Riparian trees, such as willow, cottonwood, box elder and sycamore are notorious for shedding big limbs unexpectedly.

Spontaneous limb failure occurs if limbs are unable to support their own increasing foliar weight. Bloom can add significant weight too. Warmth promotes the vascular activity that increases foliar weight. Humidity and insufficient air circulation inhibit evapotranspiration (evaporation of foliar moisture), which typically compensates for increasing foliar weight.

As the terminology implies, spontaneous limb failure occurs suddenly, and often without warning. It is therefore potentially very dangerous. It is common among limbs that exhibit no prior structural deficiency. Even experienced and educated arborists who are familiar with vulnerable tree species can not identify and mitigate all potentially hazardous limbs. 

Arborists often suggest pruning to limit the weight of trees that are innately susceptible to spontaneous limb failure. However, limbs that are already sagging from their own weight are risky to engage. Most damage occurs in spring and early summer. Fruit trees that are too productive can succumb to the weight of fruit as it ripens through summer or autumn.

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Cold Winters Have Certain Advantages

Winter frost can improve spring bloom.

Even in May, damage from the frosts of last winter is still evident among some of the more sensitive plants. Lemon trees and bougainvilleas that have not yet been pruned may still display bare stems protruding above fresher new growth. Some bougainvilleas did not survive. Those that are recovering will bloom later because replacement of foliage is their priority for now.

However, peonies, although rare, are blooming better than they have since 1991, right after one of the worst frosts in recorded history. Earlier, some lilacs, forsythias and wisterias likewise bloomed unusually well. While so many plants were succumbing to cold weather, many others were enjoying it.

The reason that peonies typically do not seem as happy locally as they are in severe climates is that they really prefer more cold weather while they are dormant through winter. Without it, they may not go completely dormant, or may not stay dormant long enough to get the rest that they need; and then wake up tired in spring. Cold winter weather promotes more adequate dormancy, which stimulates healthier growth and bloom this time of year. It all makes sense considering that peonies are naturally endemic to colder climates.

A preference for cooler winter weather is also why so many varieties of apples and pears that are grown in other regions do not perform well here. The good news is that as the fruit of local apple and pear trees matures through spring and summer, it may be of better quality that it has been for many years. Trees that typically produce sparsely may produce more abundantly this year. The weather that damaged tropical and subtropical plants was an advantage to others.

Nothing can restore cherries, apricots, peaches and any other early blooming fruit that was dislodged by late rain, but any fruit that survived may be just as unusually good as apples and pears. Not only is the best place for gardening, but minor weather problems can have certain advantages.