Concrete And Jungle Can Be Compatible

80620thumbConcrete is one of the most common of landscape materials. There are probably more landscapes that include concrete of one form or another than there are landscapes that include lawn, and most landscapes include lawn. There are more landscapes that lack shade trees than there are without concrete. We do not notice it much because, once it is installed, we do not do much to it.

Concrete gets poured into our gardens as a liquid like slurry of cement and sand and gravel aggregates that cures into a stone-like solid. It is not ‘cement’, but cement is the component that binds it all together. Almost all modern concrete is reinforced with steel of some sort to prevent it from breaking as easily as old unreinforced pavement does. It can be as permanent as we want it to be.

Concrete is used to pave patios, driveways and sidewalks, and gets molded into stairs, curbs, and the foundations and slabs for our homes and garages. The visible surfaces of concrete can be colored, textured or outfitted with stone to look better in the landscape than simple bare concrete. It is relatively ‘low-maintenance’, but should sometimes get swept or blown if debris accumulates.

Concrete is a versatile and durable material, but is no more perfect than anything else in the garden. It inhibits percolation of moisture and gas exchange in the soil below. Because it is inflexible, it fractures if displaced by roots or settling soil. Glare from paved surfaces can enhance sun exposure enough to roast sensitive foliage and exposed bark. Certain foliar debris can stain concrete.

Concrete limits plant selection. Conversely, the presence of mature trees limits the location and quantity (surface area) of concrete to be installed. Trees with aggressive roots or big trunks should not be planted so close to concrete that they will have no choice but to displace it. Root barriers help with mid sized trees, but are not always effective forever. Dogwoods,Japanese maples and other plants with sensitive foliage or bark, are more vulnerable to exposure if concrete around them is also exposed.

Watering Starts Where Rain Finishes

70607thumbFor a while last winter, it seemed like the rain would never stop. Obviously, it did. The warm spring weather that followed helped plants to take advantage of the rare surplus of moisture. Desert wildflowers were more colorful than they had been in many years, and maybe since 1983 in some areas. Now the weather is back to normal for here, and we must water our gardens accordingly.

There is nothing natural about irrigation (watering); but then, there is nothing natural about gardening or landscaping. Most of the plants in common landscapes are not native. They were imported from vastly diverse regions with very different climates. Because this happens to be a semi-arid ‘chaparral’ climate, most plants want more moisture than they would get here naturally from rain.

Adapting unnatural irrigation to unnatural landscaping sounds easy enough. The problem is that the many different types of plants from so many different climates each want something different. Also, some plants need unnaturally frequent irrigation to sustain unnatural behavior. For example, lawn grass that would naturally go dormant after a dry summer needs water to stay green all year.

Lawn grasses have finely textured roots near the surface of the soil, so want frequent irrigation. Trees within lawns might want larger volumes of water to reach lower roots, but do not like frequent irrigation that keeps the surface of the soil moist. The sort of regular irrigation that is good for lawn promotes shallow tree roots that ruin lawns and pavement, and are not exactly ideal for stability.

Automated irrigation is usually set to operate very early in the morning, and finish before anyone in the home is likely to be outside, or using much water inside. (Other water use can compromise pressure.) Less water evaporates before the sun comes up. Watering before midnight might seem like a better idea, but keeps foliage wetter longer, so might promote fungal diseases such as mildew. Frequency and duration (volume) of irrigation require occasional adjustments to adapt to the weather.

The Birds And The Bees

80613thumbThere is so much more to gardening than mere horticulture. There is so much more to horticulture than mere plant life. Plants get eaten by insects and animals, and also take advantage of insects and animals for pollination and dispersion of seed. Some of us who enjoy gardening also like to attract some types of animals and insects to our gardens because they are nice to have around.

The birds and the bees, as well as butterflies, squirrels, lizards, snakes and other small animals add color, motion and vibrancy to the garden. Destructive animals like gophers, rats and deer, and cumbersomely big animals like moose and bears, are not so popular. Mosquitoes and flies are the sorts of insects that we would like to repel with aromatic herbs. Some but not all are welcome.

‘Pollinator’ flowers have become a fad recently, not only to attract bees, but also to provide them with more of what some believe they are lacking out in the wild. There is certainly nothing wrong with attracting bees. Those who are enslaved in honey production are best! Children learn as much about nature from bees as from other wildlife. The soft hum of big herds of bees is quite nice.

Beyond that, we should think outside the box of our home gardens. The unnatural disruption of local ecology can not be repaired by throwing more unnatural resources at it. Honeybees who were imported to make honey are not native, but displaced and interbred with natives enough to interfere with their natural pollinating behavior, as well as their resistance and susceptibility to disease.

Almost all plants in urban as well as agricultural areas were imported too. They were perpetuated until they dominated the localized ecosystems. There is now much more flora in places like the Los Angeles Basin and the Santa Clara Valley than there has ever been before! There is no shortage of bloom for bees. In fact, there is an overabundance of bloom potentially distracting bees from pollinating native specie who need them. Invasive exotic eucalypti might enjoy their popularity at the expense of California poppy.

Grapes And Vines Of Wrath

70531thumbAnyone can plant a grapevine. With a bit of work, almost anyone can make a grapevine grow. Most who put forth the effort can figure out how to prune and cultivate a grapevine. Yet, grapevines so often get very out of control. They easily escape confinement, overwhelm nearby plants, climb into trees and overburden their trellises or arbors. It is easy to forget how aggressive they can be.

The primary problem with aggressive vines is that they require pruning for confinement. The most aggressive vines need the most aggressive pruning. Grapevines can actually be quite docile if pruned properly. Chinese wisteria and red trumpet vine need even more aggressive pruning, and will never be completely tamed. It is important to know the personality of each vine in the garden.

The secondary problem with aggressive vines is they are expected to conform to unrealistic confinement. Small trellises that are lower than about eight feet, including common gate arbors, spires and obelisks, are really only big enough to accommodate docile small vines like clematis (hybrid), American wisteria, well pruned mandevilla and vining annuals like morning glory and pole bean.

Chinese wisteria, large types of bougainvillea and other big and heavy vines need big and stout trellises or arbors. Lattice will not do. Chinese wisteria becomes entangled with lattice, and then crushes it as the vines expand. Bougainvillea does the same to a lesser extent, but then pulls the lattice apart as the intertwined vines sag from the increasing weight of foliage and growing vines.

Clinging vines like creeping fig and Boston ivy present another problem. They are not interested in trellises or arbors. They do not grab onto support by twining stems or tendrils. They instead cling directly to surfaces with specialized aerial roots that damage paint, stucco or even bare wood fences. Clinging vines should therefore only be allowed to climb surfaces that they will not ruin, such as concrete walls. They are better vines for freeway soundwalls than for home gardens.

Naturalizing Might Be An Advantage

80606thumbOf course, to the plants who do it, naturalizing is an advantage. To the rest of us, it is often a problem. The advantage to the plants who do it is that they move into new territory, make themselves at home, and probably do quite well with the new place. The disadvantage to everyone else is that naturalizing plants may not play well with others, and consequently interfere with the ecosystem.

Most of the naturalizing plants whom we are aware of are aggressively invasive exotic (non-native) specie, such as Acacia dealbata, pampas grass, blue gum, broom and reed. They move in and compete with or exclude native vegetation. Some might interfere with native fauna as well. (All those monarch butterflies who swarm blue gum are ignoring specie who rely on them for pollination.)

Locally native plants can not naturalize because they are naturally there already. Therefore, all plants who naturalize are exotic. However, not all naturalized exotic specie are aggressively invasive. Some who can not survive without irrigation in the local chaparral climate may never get farther than being a weed in landscaped areas. Some bulbs may not spread from where they are planted.

Rose campion, sweet alyssum, cosmos, forget-me-not, four-o’-clock and nasturtium can replace themselves faster than they die out, but only where they get enough water. Some of the seedlings are likely to appear in situations where they are not wanted. Some might grow into situations where they might be desirable. There is no shame in allowing the desirable ones to continue growing.

Many of the most extensively bred garden varieties eventually revert to something more similar to their ancestors. For example, most of the fancier modern varieties of nasturtium, after a few generations, will bloom with more of the basic yellow and orange than they did when they were new. Eventually, almost all flowers will be yellow or orange. Such seedlings are known as ‘feral’, because they are more similar to the wild ancestry of nasturtium, than to the genetically unstable modern variety that was originally sown.

Flowers For Home And Garden

70524thumbThere is a difference. Hybrid tea and grandiflora roses were bred to be excellent cut flowers for the home. They bloom on long stems, and last well once cut. However, the rigid and thorny plants that produce these excellent blooms are realistically not much to look at. Floribunda, polyantha and climbing roses are more of a compromise with less ideal (perhaps) flowers on friendlier plants.

Conversely, bearded iris are spectacular while blooming out in the garden, but do not last so well as cut flowers. As colorful as they are, they perform best while still attached to the plants that produced them. Fading flowers might be groomed away from flowers that continue to bloom later, but are not a serious problem if allowed to linger. The garden is more forgiving than the home.

Where space allows, rose gardens or cutting gardens are areas devoted to the production of flowers for cutting and bringing into the home. Like vegetable gardens, cutting gardens might be hedged, fenced or partly concealed from the rest of the landscape. No one minds if the utilitarian plants within get deprived of their flowers, or need to be staked or caged like big tomato plants.

Taller and bulkier varieties of dahlia, delphinium, lily, Peruvian lily (alstroemeria) or sunflower that might be to big and awkward elsewhere in the garden can be right at home in a cutting garden. Compact and more prolific varieties of the same flowers work better in more prominent parts of the garden, and if prolific enough, can also provide flowers (although less spectacular) for cutting.

There are very few rules in regard to cut flowers. Many of us bring in bearded iris or daylily, even though they may not last more than a day. The buds below the flowers might bloom afterward. Blooming clematis vine, nasturtium (on or off stem), lily-of-the-Nile, zonal geranium, bougainvillea, bottlebrush, crape myrtle and even flower stalks of New Zealand flax, are all worthy cut flowers for anyone wanting to try them, especially if the garden provides enough to spare.70524thumb+

Overgrown Shrubbery Becomes Small Trees

80530thumbThose of us with ‘maintenance gardeners’ are likely aware of how rare it is to find someone who knows how to maintain hedges properly. It seemed so simple years ago. Several identical plants could simply be planted in a row, and then somewhat regularly shorn for confinement to a prescribed space. They were not allowed to exceed a specific height or width for long between shearing.

Formal hedges are now passe. They do not conform to modern landscape style. No one wants to maintain their formality anyway. If a gap develops, it is likely to be filled with a different cultivar or species that is not identical to the rest of the hedge, merely because it happened to be available at the nursery. Feral or invading shrubs, vines or even trees get shorn right into the whole mess.

Then there is the problem with bloat. Rather than staying confined, hedges typically get slightly larger with each shearing. What is worst is that most of the extra bulk is high up and shading lower growth, causing it to grow slower. Hedges eventually develop that all too familiar top-heavy appearance, and encroach into otherwise usable space that they were designed to provide privacy for.

There are few simple options for hedges and shorn shrubbery that have gotten too big for their space. Some can be renovated and cut back beyond their outer surfaces, but recovery will take a bit of time, and can not fix unmatched plants. However, such restoration is likely better than replacement. Just like for a new hedge, feral and invading vegetation must be removed in the process.

Another option is to completely change the form of improperly shorn shrubbery to small trees. This can be done with individual shrubs, or a few selected remnants of an otherwise removed hedge. Cherry laurel, photinia, bottlebrush, tea tree, privet, various pittosporums and many other large hedge shrubs work quite nicely. Rather than getting pruned back into submission, the lower growth gets pruned away to expose sculptural trunks within, and the upper growth gets pruned only for clearance above.

A Hedge Between Keeps Friendship Green

70517thumbIf good fences make good neighbors, what about hedges? If only it were that simple. There are all sorts of evergreen hedges to provide privacy, obstruct unwanted views, disperse wind, define spaces, or muffle noise. They can do much of what fences do, and muffle sound better. The problem is that they are composed of living plants, shorn into submission and very unnatural shapes.

Unlike fences, hedges need to be shorn very regularly. Otherwise, the shrubbery that they are composed of tries to grow into its natural forms. Slow growing plants like Japanese boxwood may only need to be shorn twice annually, especially if no one minds if it looks somewhat shaggy. Old fashioned glossy privet is so vigorous that it likely needs to be shorn a few times before autumn.

Even if the work of shearing is not a problem, accessibility might be. Hedges are popularly planted between properties. The outsides of such hedges are therefore accessible only from adjacent properties, which might have other plants or landscape features in the way. There is also the risk that the neighbors might not want anyone coming over to shear such a hedge! Beware of the dog!

Hedges in conjunction with backyard fences are easier to maintain as long as they are kept below or at the same height as their fences. They only need shearing on the inside and on top. Fences might be needed to keep dogs in or out anyway. When planning for a new hedge, other plants and garden features that might obstruct access within the same landscape must be considered too.

Taller hedges should be shorn so that they are slightly narrower on top, and wider at the bottom. This promotes more uniform growth, and hopefully prevents basal baldness. Upper growth gets more sunlight than lower growth, so grows faster, and too often shades out lower growth while becoming distended up high. Hedges should also be watered and fertilized evenly from end to end.

It is important to remember that hedges work for the landscape, and should not be allowed to dominate. Fat hedges waste space. A well groomed hedge that is only two feet from front to back works just as well as a hedge that is three times as plump. Feral plants that ‘volunteer’ within a hedge must be removed instead of shorn along with the hedge. They only compromise uniformity.

Tropism Gives Plants Some Direction

80523thumbWhen a seed germinates, the roots know that they want to go down, and the new stem knows that it wants to go up. Going up sounds simple enough. Stems just go towards the light. How do they know where the light is while they are still under the soil? Well, new stems go upward for the same but opposite reason that roots go downward; gravity. Roots go toward it. Stems go away from it.

Tropism is how plant parts respond to a variety of stimuli, particularly gravity and light, but also water, chemicals, mechanical stimulation, trauma and electricity. Response to gravity is geotropism. Roots exhibit positive geotropism by growing towards gravity. Stems exhibit negative geotropism by growing away from gravity. Stems exhibit positive phototropism by growing towards sunlight.

Roots are always figuring out where to go next by prioritizing their innate positive geotropism, their tropism for or against certain chemicals, and their tropism for moisture but against saturation. Until we see them migrating into lawns, displacing concrete or getting into a septic systems, their work underground is unseen. Tropisms above ground are quite visible and perhaps informative.

When a tall herbaceous plant falls over, it tries to get up. If unable to, it can at least curve new grow upward. Even cut flowers and vegetables in the kitchen can do that much. Snapdragons that are initially arranged leaning outwardly from the center of a floral arrangement can go vertical within a day or two. The fluffiest houseplants regularly get turned so than they do not favor one sunny side.

Trees are too big to move, but on rare occasion, it happens. The crossed pairs of Mexican fan palms commonly planted outside of In-N-Out Burger restaurants get planted at a lean while mature, but then grow vertically after installation, leaving an angular kink where the direction changed. Such a kink in an otherwise straight trunk of a tree that was not planted at an angle might indicate a sudden destabilization. A curved trunk indicates either a slow destabilization, or tropism to escape shade.

Foliage Shows Its True Colors

70510thumbFlowers were originally colorful only to attract pollinators. Breeding has improved the color and quality of many garden varieties of flowers, to make them more appealing to the people who grow them. Some have been bred so extensively that they are sterile, which defeats the original function of flowers. Now their function is merely to look good in the garden. Improvements are relative.

Foliage is green because it is photosynthetic. Chlorophyll, which is necessary for photosynthesis, happens to be green. Yellow, red, blue, purple, bronze, gray and variegated foliage might not be as efficient at photosynthesis as green foliage, but can be appealing in home gardens. Many plants with colored foliage are inferior to their greener counterparts, but are somehow more popular.

Gray and blue foliage absorbs less sunlight, which can be an advantage in harsh environments. Blue hesper palm and the various blue agaves are from arid deserts. Colorado blue spruce is from high elevations of the Rocky Mountains. Arizona cypress, silver mountain gum, artemesia, lambs’ ears, lavenders, dusty millers and blue junipers all provide distinctively gray or blue foliage.

Golden arborvitaes and junipers can be strikingly gold as new foliage develops in spring, even if the color does not last long. Most plants with gold foliage fade to yellowish green through summer. Golden honeylocusts do not fade as much, so are still mostly yellow by the time they defoliate in winter. Purplish or reddish foliage of purple leaf plum and red Japanese maple holds color better.

Euonymous, English holly, osmanthus, silverberry, hosta and various pittosporums can be variegated with white or yellow. Ivy, and hydrangea can be variegated with white. New Zealand flax and mirror plant can be variegated with gold or bronze, . . . or red or pink. Any unvariegated mutant growth (known as ‘sports’) that appears on variegated plants should be pruned away. Because it has more chlorophyl, it grows more vigorously, so can overwhelm and replace the more desirable variegated foliage.70510thumb+