Posted on by tonytomeo

Arid Climates Can Be Challenging

Some plants shrivel in arid warmth.

‘Mediterranean’ translates as an adjective that describes being at the middle of the Earth. Those who inhabited that region many centuries ago considered the Mediterranean Sea to be central to their World. That was long ago and far away. Nonetheless, climates here and now are somehow Mediterranean. Maybe semi arid climates of Italy are Californian.

Mediterranean climates are temperately warm with dry weather through summer. Rain is almost exclusive to a rainy season between autumn and spring. Although rain can briefly get abundant during the rainy season, the average annual rainfall is modest. Humidity is minimal for much of the time. Arid warmth is more comfortable than rarely humid warmth.

Desert climates accumulate less than ten inches of rain annually. Local climates receive more than fifteen inches of rain annually. They are therefore not sufficiently arid to qualify as desert climates. Technically, they are only semi arid chaparral climates. This climactic designation is perhaps more appropriate than the regional designation of Mediterranean.

Native plants and plants that are native to other chaparral climates are naturally pleased with the local climate. However, some initiate at least partial dormancy to survive through the long and arid summers. They may bloom early, but then partially defoliate for several months. Some delay dormancy if watered. A few dislike watering. It is unnatural for them.

Most plants in home gardens are not native to chaparral climates. They require watering to compensate for aridity during summer. Minimal humidity accelerates evaporation from foliar surfaces, which increases the demand for moisture. In conjunction with warmth and wind, aridity can desiccate foliage. Like people and pets, plants must maintain hydration.

Humid warmth that is less comfortable for people and pets is more comfortable for plants than arid warmth is. Humidity inhibits evaporation from foliar surfaces so plants consume less moisture. Incidentally, most pathogens, such as fungal diseases, bacterial diseases and most insects, also prefer warm humidity. People and pets seem to be in the minority.

Posted on by tonytomeo

Drought Tolerance Necessitates Root Dispersion

Extensive root dispersion enhances drought tolerance.

Fads certainly complicate gardening. Most are merely marketing tactics. Most are bogus. Many even contradict their justifications! For example, most new, trendy and supposedly sustainable plant cultivars are genetically weak because of extensive breeding. Drought tolerance likewise has potential to be a constructive fad, but is so commonly misapplied.

Incidentally, its terminology is somewhat inaccurate. Drought is an extended but unusual pattern of dry weather. Whether the duration is for one year, or many, it is not permanent. The dry weather that persists through summer locally is normal for the chaparral climate. It is therefore a normal characteristic of climate, rather than abnormal weather conditions.

Drought tolerance is therefore practical here as chaparral tolerance. Most plants that are drought tolerant are naturally endemic to chaparral regions or deserts. Many of the native species naturally exhibit remarkable drought tolerance. Once established, they might not require any more moisture than they get from annual rainfall. Some prefer dry conditions.

Drought tolerance should not imply that such plants are undemanding. In some regards, they are more demanding and less adaptable than plants that require frequent watering. Such plants rely on extensive root dispersion to procure the moisture they require within dry situations. Most do not adapt to confinement, even if watering is enough to cause rot.

Container gardening is therefore a fad that is incompatible with drought tolerance. It only uses less water for plants that use more water. Also, modern drip irrigation, which is very practical for plants that rely on irrigation, requires a bit more effort for plants that use less moisture. To not promote rot, emitters must move farther from main trunks as plants grow.

Many of the most sustainable and drought plants are old fashioned sorts that became too common years ago. Fortunately, some are regaining popularity again. Some of the more compact eucalypti are proportionate to modern gardens. Grevillea, bottlebrush, rockrose, juniper, rosemary, salvia, lavender and New Zealand flax are as drought tolerant as they had always been.

Posted on by tonytomeo

Foliar Color Goes Beyond Green

Foliar color can exceed floral color.

New England is famous for spectacular foliar color through autumn. Such color is merely seasonal though, and almost exclusive to deciduous vegetation. With few exceptions, its color range is limited to variations of yellow, orange, red or brown. It happens thousands of miles away, and is difficult to replicate on such a grand scale with locally minimal chill.

For smaller scale home gardens, there are many options for foliar color at any time of the year, regardless of chill. Some are deciduous. Most are evergreen. Colorful foliage might exhibit variegation or monochromatic coloration. Variegation might involve stripes, spots, borders, veining, or any combination of divergent colors. Some might entail a few colors.

Besides autumnal yellow, orange, red or brown, foliage can be pink, purple, blue or gray. Variegation can feature any of these colors, as well as white. The size and form of plants with foliar color ranges from small annuals and perennials to vines, shrubbery and trees. A few of such plants that are deciduous might change to different colors through autumn.

Various Hosta, Euonymus, Coprosma, Pittosporum, Hedera and Bougainvillea are some of the more popular plants with white or yellow variegation. New Zealand flax is popular for bronze, brown, gold or pink variegation. Canna can display evenly bronze or purplish foliage, white patches on green foliage, or neat yellow and pink stripes of varying widths.

Purple leaf plum and some cultivars of smoke tree, beech Eastern redbud and Japanese maple have the best purplish foliage. Other cultivars of smoke tree, as well as arborvitae, juniper, Monterey cypress and honeylocust, generate impressively yellow foliage. Agave and blue spruce contribute soft blue. Coleus impresses with various color combinations.

Whether deciduous or evergreen, most colorful foliage displays its best color while fresh and new in spring. For some, color fades through summer. Junipers that are gold through spring may be plain green by summer, particularly in dry conditions. Although light colors and variegation are appealing within shady situations, shade can inhibit such coloration.

Posted on by tonytomeo · 2 Comments

Simplicity Is Best For Parkstrips

Clumping grasses hang out over curbs.

Parkstrips, those narrow spaces between curbs and sidewalks, are among the most awkward spaces in the garden. In urban areas with significant traffic, they are commonly paved over. Some neighborhoods, especially downtown neighborhoods, do not have parkstrips at all. Suburban neighborhoods though, often have wider parkstrips.

The difficulty with parkstrips is that there is so much happening around them. Cars get parked on one side. Pedestrians pass by on the other side. Driveways need to be kept clear at each end. Water meters and perhaps other subterranean utilities must be accessible.

Street trees are common features in parkstrips. They should have complaisant roots that will be less likely to displace the surrounding pavement and curbs, and high branch structure for adequate clearance above truck traffic on the roadways below. Ideally, street trees should conform with the neighborhood, and are often quite uniform. Selection of street trees should be a community effort where practical.

All other plants that go into parkstrips should be adaptable to confinement within the limited space available. They should not extend over curbs or sidewalks where they can scratch parking cars or be obtrusive to pedestrians. Parkstrip landscapes must also stay low enough so that they do not obstruct the view from cars backing out of driveways.

Because people regularly walk past or through parkstrips, thorny plants like cacti and roses should be kept back from the edges, or preferable not put into parkstrips at all. Large agaves and yuccas (with rigid leaves) are simply too big and dangerous for narrow parkstrips.

Contrary to the trend of planting vegetables in weird places, parkstrips are not good places for them either. The main problem is what dogs like to do in parkstrips. The second problem is that the good produce that might be out reach of dogs is within reach of everyone else walking or driving by. Reflected glare from all the surrounding pavement is a problem for plants that do not like harsh exposure.

Really, there are far more limitations on parkstrip landscaping than there are options. Turf grasses or tough ground cover that tolerates traffic, like trailing gazania, may seem to be a mundane, but they are practical. At least ground cover can be punctuated with clumping perennials like African iris, lily-of-the-Nile or blanket flower.

Pots are overrated, especially for curbsides.
Posted on by tonytomeo · 2 Comments

Shear Hedges Seasonably And Properly

Scheduling is important to hedging too.

There are rules to hedging. For example, hedges should be uniform and exclusive to just a single cultivar. A modern ‘Green Beauty’ boxwood will never conform within a hedge of more yellowish old fashioned boxwood. Hedges should also remain within confinement. It is important to shear them back from obtrusion into walkways and other usable spaces.

It is not as simple as it seems to be. That is why so few hedges get proper maintenance. Almost all occupy and therefore waste more space than they need. Most have wide tops that shade out narrower lower growth. Moreover, many plants that are not components of hedges all too commonly succumb to inappropriate shearing too. It is sheer shear abuse!

Even if done properly, only hedges and a few other plants are conducive to shearing and hedging. It is an aggressive procedure that compromises form, texture and bloom cycles of involved plants. For hedges, that is not a problem. They need not bloom, and adapt to a refined hedged form, which is more desirable than their natural shrubby form would be.

However, it is important to not unnecessarily shear plants that bloom, or provide intricate foliar texture or form. Shearing deprives rhododendron of young floral buds. It ruins foliar texture of Heavenly bamboo, and foliar form of Japanese maple. It is acceptable to shear boxwood only because it responds by generating such appealingly uniform foliar growth.

With proper scheduling, it is possible to shear only a few blooming plants without ruining all of their bloom. Aggressive shearing after the early bloom of oleander and bottlebrush leaves them with space to grow enough to bloom again during autumn. Without sufficient space to grow, they will require subsequent shearing, which will ruin subsequent bloom.

It is better to shear some of the simpler hedges, such as privet and boxwood, shortly after winter. They regenerate lush growth immediately afterward, and do not mind two or three annual shearings. The last shearing should be early enough to allow a bit of growth prior to autumn. Photinia generates appealingly bronzed new growth in response to shearing. Also, frequent shearing inhibits potentially undesirable bloom.

Posted on by tonytomeo · 3 Comments

Can’t See The Forest For The Trees

Even small trees can become obtrusive.

Foliage is often employed to obscure views. Evergreen shrubbery or trees can provide privacy in the garden or for windows. It can just as easily hide unappealing buildings in the distance, or driveways where cars get parked. Unfortunately, too much foliage often obscures desirable views or interferes with lighting.

There are all sorts of reasons to control greenery that might otherwise get overgrown. Overgrown shrubbery and trees not only hides the architectural appeal of a home, but can also be a security risk by concealing windows and doors that burglars might break into, and by obscuring security lighting and street lights. Too much shade prevents lower plants from getting the sunlight they need.

The best way to limit overgrowth is by selecting plants that stay proportionate to their intended functions. For example, shrubbery below windows should naturally stay lower than the lower windowsills. Shade trees for areas where views should stay open should have high branch structure and relatively bare trunks. Well, most of know that this does not always happen.

The options are limited for greenery that wants to get larger than it should. Obviously, it can be pruned regularly; but this may be more work than it is worth, and can cause disfigurement Some plants can be pruned less frequently if pruned more severely, but will be bare and potentially unsightly for quite a bit of time. Overgrown plants can alternatively be removed and replaced with plants that are more proportionate to intended functions.

An option that is not often considered is an ‘updo’. Trees and large shrubbery that are obtrusive to views or lighting can be pruned up and over what they are being obtrusive to. For example, lower growth of large pittosporums that is covering low windows can be pruned away to expose bare inner trunks supporting higher growth. The lower trunks can be appealingly sculptural without being too concealing. This works nicely for large shrubbery like viburnum, bottlebrush, oleander, photinia and pineapple guava.

Street trees that interfere with street lights (or marquis on storefronts) may need to be updo pruned a few times for adequate clearance, but these procedures are much less work, are less disfiguring to the affected trees, and produce more appealing results than keeping trees down.

Posted on by tonytomeo

Nature Is Not Naturally Accommodating

Many trees naturally exhibit irregular form.

Gardening is quite unnatural. It involves unnatural cultivation of mostly unnaturally exotic (nonnative) species of plants. Irrigation delivers more water than seasonal rain provides. Fertilizers contribute more nutrients than endemic soils provide. Pesticides, if necessary, inhibit proliferation of pathogens. Nature simply could not accommodate such demands.

Not only is gardening unnatural, but it also interferes with established ecosystems. Many aggressively invasive plants were formerly desirable exotic plants that naturalized. Many pathogens arrived with exotic plants. Several naturalized plants have potential to distract native pollinators from native plants that rely on their pollination. It is an ecological mess.

Nonetheless, it works. Gardening within the constraints of nature would be unproductive. Most residents of California inhabit chaparral or desert climates that originally sustained limited vegetation. Such limited vegetation sustained a very limited indigenous populace within relatively vast areas. Modern residential parcels would be completely inadequate.

That is the justification for gardening, whether for sustenance, or merely to beautify home environments. Unnatural breeding continues to improve performance of many useful and appealing plants. Unnatural horticultural techniques generate more desirable vegetation within confinement of urban gardens than would naturally inhabit a few acres in the wild.

Nature remains relevant though. All plants originated within nature somewhere. Besides their basic requirements, exotic plants prefer environmental conditions that are similar to those of their natural origin. Some tropical plants crave more warmth and humidity. Some plants prefer more winter chill. Most popular exotic plants rely on supplemental irrigation.

Physical characteristics of many plants necessitate special accommodations also. Roots of plants that naturally compete in dense jungles are likely to damage pavement. Without adequate pruning, native plants that naturally exploit burn cycles can become perilously combustible. Many vines naturally try to overwhelm nearby vegetation and infrastructure.

Posted on by tonytomeo

Vines Have Unique Personalities

English ivy clings with aerial roots.

Boston ivy and creeping fig are good aggressive vines for freeway overpasses and sound-walls. They are resilient to harsh exposures and pollution, and help to muffle the sound of traffic. Boston ivy provides remarkable foliar color in autumn before defoliating in winter. Creeping fig provides thick evergreen foliage that overwhelms any graffiti that it can reach.

However, their aggressive behavior that is such an advantage on freeways is precisely why they are not so practical for home gardens. Boston ivy gets around so efficiently because it grabs onto surfaces with ‘holdfast disks’ (modified tendrils) that damage paint, stucco, wood and just about anything that is not built like a freeway. Creeping fig is at least as destructive with clinging aerial roots, as well as constrictive stems that can crush smaller plants, fences and anything else that it might grab hold of.

Most vines are aggressive in nature. They exploit trees for support, and then compete with them for space. Some are complaisant enough to mingle relatively peacefully with the trees that support them. Less honorable vines have no problem overwhelming the canopies of their supportive trees. Creeping fig and other related figs are known as ‘strangler figs’ because their constrictive roots and stems crush and kill the same trees that help them get above the forest canopy.

Such behavior needs to be considered when selecting vines for home gardens. Bulky and potentially constrictive wisteria vines that would tear lattice apart can be quite appealing on sturdy arbors or trellises. Lattice could instead be adorned with docile Carolina jessamine, lilac vine, mandevilla or even regularly pruned passion vine. Star jasmine and the various trumpet vines work nicely to obscure chain link fences. With regular selective pruning, pink jasmine, honeysuckle and potato vine work well on rail fences.

Climbing roses and bougainvillea do not climb on their own, but can be trained almost like vines. Some varieties stay small enough for low fences and trellises. Larger types are proportionate to larger fences and arbors.

Posted on by tonytomeo

Streets Might Benefit From Shade

Proportion is important for street trees.

Shade has become less of a priority for modern urban gardens than it still is for older and more spacious suburban gardens. Significantly less sunlight reaches the ground of such confined gardens among taller and shadier homes and fences. Even where shade might be desirable, space for shade trees might be minimal. Streets are the primary exception.

Streets, and associated curbs and sidewalks, are generally the sunniest situations within modern urban neighborhoods. They collect and radiate ambient heat that warms nearby homes and gardens, even if the weather is already unpleasantly warm. Cars that park on pavement without shade are vulnerable to the most heat, which accelerates weathering.

It is an unfortunate waste. Sunshine that is useless and undesirable on streets would be useful within gardens. Although sunlight is not transferable from one situation to another, it might be partially abatable with shade. Streets are certainly no place for gardening; but the space above them may have potential to accommodate the canopies of shade trees.

Street trees are simply trees that flank streets and other roadways. Most are shady. A few are merely visually appealing. They may inhabit parkstrips, treewells or gardens that are adjacent to sidewalks. Many municipalities prescribe street trees for most of their streets. Conforming street trees are standard accessories for streets within new residential tracts.

Of course, street trees must be appropriate to their particular applications. They must get tall enough for clearance above the largest of vehicles that use the roadways below. For commercial districts, some must also stay above storefront signs. Contrarily, a few street trees must stay below aerial utilities. Street lamps, high or low, require clearance as well.

Size and form are not the only considerations. Roots of street trees must be complaisant with infrastructure. Mess should be as minimal as practical. The most complaisant street trees might stay too small to attain adequate clearance or provide much shade. The most visually appealing might be too messy. Selection of appropriate street trees necessitates significant research regarding every potential option.

Posted on by tonytomeo · 2 Comments

Watering Water Wise Plants

Excessive watering rots drought tolerant yarrow.

Native plants like coast live oak, valley oak, toyon, flannel bush, Western redbud and California lilac (ceanothus) are among the most resilient of plants as the weather gets dry and warm after spring. So are plants from similar climates, like bottlebrush, oleander, rockrose, grevillea, acacia and eucalyptus. They survive dry summers by dispersing their roots deeply into soil that does not get as desiccated as surface soil naturally does (without irrigation).

Ironically, these most resilient plants can also be difficult to work with while they are young. Because they rely on extensive root dispersion for survival, new plants that have not yet dispersed their roots can not survive long without regular watering. They only become tolerant to drought as their roots disperse into deeper soil.

However, because they are adapted to arid conditions, they do not like to be too damp for too long. Roots soon rot in soil that does not drain adequately between watering. They therefore need to be watered frequently, but not too frequently. Yes, that is as confusing as it sounds.

To make it even more confusing, these plants will need less watering as they mature and disperse their roots. Bottlebrush, oleander, contoneaster, hop bush, firethorn, grevillea and juniper can certainly tolerate more water than they really need; but wasting water is contrary to selecting drought tolerant plants to conserve water. Manzanita, coyote brush, rockrose, flannel bush and redbud may actually succumb to rot if watered too much. Even perennials like Pacific coast iris and yarrow can have problems.

Pine, oak, acacia and especially eucalyptus disperse their roots as soon as they can, so do not want to be confined in containers. It is therefore best to plant smaller young specimens than larger ones. #5 (5 gallon) eucalypti get established in the garden more efficiently than larger but more expensive #15 (15 gallon) trees. If #1 trees were available, they would be even better.