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Eucalypti Are Innately Drought Tolerant

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Distinctive foliage provided by red ironbark.

Drought is nothing new here. There could be plenty of rain next winter and for years afterward; but eventually, there will be another series of dry winters, prompting rationing all over again. Landscapers and big box garden centers continue with business as usual. It is up to us to manage our gardens responsibly. Besides native plants, aloes, yuccas, junipers and eucalypti are four groups of formerly popular, drought tolerant plants that are worthy of more attention again.

Eucalypti had gotten a bad reputation even before they became popular the last time around. Tasmanian blue gum, Eucalyptus globulus, that was planted so extensively for wood pulp and timber throughout California, is a huge and extremely messy tree. Yet, it is still the most familiar of the eucalypti.

Garden varieties of eucalypti are much more docile. Even though they drop their evergreen foliage and hard seed capsules throughout the year, they do so on a smaller scale. The tall and elegant lemon gum constantly sheds strips of bark like the Tasmanian blue gum does, but does not get big enough to be too overwhelming.

Because they are so undemanding, and some are somewhat messy, eucalypti are best in unrefined parts of the landscape, and away from lawn. Their mess is no problem over ivy or iceplant. They are happiest where other trees might be unhappy. Generous watering actually inhibits root dispersion, and can cause vigorous but structurally deficient stem growth.

Eucalypti innately prefer to be planted while very young, even from four inch or one gallon (#1) pots. Larger (and more expensive) trees, such as boxed trees, take so long to get established that they get passed up by faster growing tiny (and less expensive) trees. Because they are sensitive to confinement, eucalypti are unfortunately rare in nurseries.

The online catalog of Annie’s Annuals and Perennials, which is famous for excellently weird and undemanding plants, features lemon flowered mallee, red capped gum, silver princess gum, bell fruited mallee and fuchsia gum, all in four inch pots. The bell fruited mallee and fuchsia gum are like large but airy shrubbery that do not get much taller than the eaves.

Posted on by tonytomeo · 18 Comments

Blue Is The Loneliest Color

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Colorado has a blue State Flower.

The majority of common pollinators are not impressed with blue. Otherwise, more flowers would be blue. After all, floral color appeals to pollinators. Each type of pollinator prefers specific colors. Plants customize their floral color to their preferred pollinators. If more flowers could attract more pollinators with blue, they would do so. Instead, they rely on colors that have worked well for them.

Green is actually the most common floral color. It is not obviously common because green flowers are generally ignored. They are the sort that rely on wind for pollination, so make little or no effort to draw attention. They are also the sort that produce the most and worst pollen, which gets carried farthest by the wind. Flowers that rely on pollinators produce coarser pollen that clings to things.

Of the many other colors that appeal to pollinators, most are significantly more complex than they appear. For example, what appears to be simple orange may appeal to pollinators that perceive it to be yellow, as well as those that are drawn to red, even if none are interested in orange. Different pollinators perceive different color ranges. Insects do not perceive red; but hummingbirds do.

That certainly could not explain why blue is such an uncommon color for flowers. It surely has more of a following than red, which is more common among flowers. Since most pollinators perceive blue, more flowers should utilize it. They could even add some ultraviolet or infrared to it, if that would make it more appealing. Nonetheless, true blue, without the influence of purple, is quite rare.

Lily-of-the-Nile and blue dawn flower are some of the more substantial species that provide exquisitely blue bloom. A few cultivars of butterfly bush bloom true blue too, but the color is not so clear and bright. Delphinium, bellflower, squill and grape hyacinth are smaller, but worthy perennials for the richest blues. Petunias, lobelia, nigella, cornflower and columbine are blue blooming annuals.

Many iris, sage and lupine provide exquisitely true blue bloom as well.

Posted on by tonytomeo · 8 Comments

Roses Have Thorns And Thorns Have Roses

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Roses certainly look innocent enough.

Thorns, spines and prickles are not often considered to be assets. The weirdly stout prickles on the distended trunks of floss silk tree are more of an oddity than an ornamental attribute. The striking spinose foliage of agaves and yuccas can be more trouble than it is worth. After all, thorns, spines and prickles are intended to repel grazing animals.

They all work the same way, but are physiologically quite different. Thorns are modified stems, like those of bougainvillea. Spines are modified leaves, like those of cacti. Prickles are modified epidermis, like those of roses. Then there are all sorts of plants with spinose leaf margins, like English holly. Such defenses can be a nuisance to those of us who must work with them.

However, they can be useful deterrents. Natal plum that seem to be so innocent can be grown as low hedges that no one would go through more than once. Firethorn (Pyracantha) makes a larger and comparably impenetrable hedge. Their potentially dangerous thorns are almost always adequately effective with their first few pokes, before they cause too much injury.

Some plants are so dangerously thorny that they should be kept at a safe distance. Cacti, agaves and some yuccas can be strategically placed near the perimeters of large landscapes to deter trespassers. They are scary enough to be visually deterrent remotely. Mediterranean fan palm looks friendlier, but is just as mean up close.

Japanese barberry, roses and the spinose foliage of English holly are relatively safe deterrents to inhibit traffic in smaller spaces. They will keep people away from windows without necessarily blocking either access for washing the windows, or views from within. In case of fire, they are not too dangerous to escape through; although roses should not be allowed to get overgrown.

Because thorns, spines, prickles and spinose foliage are unpleasant to handle, the plants outfitted with them often get less maintenance than then should. When they get overgrown from a lack of pruning, they are even more difficult to handle. It is probably better to put nasty debris into greenwaste instead of compost. Thorns and spines are hard, so linger as foliage decays.

Posted on by tonytomeo · 12 Comments

Gravitropism Gets Germinating Seeds Oriented

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Toward the light. Away from gravity.

Germinating seedlings know which way is up. Perhaps they just know which way is down. They can not see, hear, taste, smell or feel anything like we can. Nonetheless, they know which direction to extend their first root and stem. One thing that they can perceive is gravity. Gravitropism, which was formerly known as geotropism, is how they respond to gravity, or the Earth that generates it.

Positive gravitropism is why the first root to emerge from a seed extends downward toward gravity. Negative gravitropism is why the first stem to emerge from a seed extends upward away from gravity. Positive is toward. Negative is away. Roots and stems that develop after the first, disperse in other directions in response to other stimuli, but never really forget where gravity comes from.

Once a primary stem of a seedling emerges from the soil, it immediately responds to sunlight. Just as it exhibits negative gravitropism to grow away from gravity, it exhibits positive phototropism to grow toward sunlight. Since sunlight comes from above, positive phototropism is compliant to negative gravitropism. Branches will later disperse laterally to avoid the shade of other branches.

While branches are finding their way in the World, roots are doing the same. All of them can not always reach for the center of the Earth. They branch and disperse laterally as they sense that they are sufficiently deep in the soil. Those that venture too deeply sense an inhibition of gas exchange. Those that are too shallow sense if they get too warm or dry. There are a few types of tropisms.

Roots respond to moisture, nutrients, chemicals, temperature and mechanical stimulation within the soil. Branches and foliage respond to humidity, wind, temperature variations and air pollution. In order to function within their dynamic situations, plants somehow coordinate their responses to all of the many stimuli they experience. They are impressively perceptive, as well as responsive.

Even celery, green onions and leafy tops of carrot in a refrigerator can reach upward away from gravity.

Posted on by tonytomeo · 3 Comments

Succulents Know Recycling and DIY

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Scraps of succulents can mix nicely.

There are all sorts of succulent plants, ranging from finely textured small stonecrops to huge suguaro cactus. Because aloes and agaves are succulents, the closely related yuccas, such as Joshua tree and Spanish bayonet, are commonly considered to be succulents as well. Even begonias and impatiens could be considered to be succulents.

Succulent plants are some of the most distinctive plants available. Foliage can be various shades of green, as well as yellow, red, blue, orange, purplish, gray, bronze, nearly black or variegated. Leaves may be thick and fleshy like those of jade plants, or thin and neatly arranged in tight rosettes like those of aeoniums. Cacti have no real foliage, but some have flashy flowers.

Except for the larger sorts of cacti and some yucca, most succulents are very easy to propagate. Jade plants and iceplants grow very easily from stems simply stuck wherever new plants are desired. Aloes and hen-and-chicks grow just as easily from pups (sideshoots) separated from parent plants. Technically, even leaves can be rooted, and will eventually grow into new plants.

Because scraps from pruning can be used as cuttings, there is rarely any need to actually take cuttings from desirable growth. Where more Hottentot fig (freeway iceplant) is needed on a freeway, it simply gets ‘plugged’ (as cuttings) from scraps of debris from where established growth needs to be cut back to an edge. There is much more debris than can be used!

Pots of mixed succulents are ridiculously easy to grow simply be filling pots with potting soil, and then plugging bits of various succulents. All sorts of contrasting colors and forms can be mixed. As plants grow, those that dominate can either be pruned back, or given more space by removing slower plants. The removed plants need not be wasted, but can be plugged somewhere else.

Small succulents are just as easy to plug into informal walls of stacked stone or broken concrete. Some small succulents actually stabilize loose stone. Their docile and finely textured roots are not likely to do any damage.

Posted on by tonytomeo · 6 Comments

Cultivar Is A Cultivated Variety

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Most cultivars need to be cloned.

A plant ‘variety’ is a group within a species that exhibits distinguishing characteristics. A ‘cultivar’ is simply a cultivated variety. The first five letters of ‘cultivated’ merged with the first three letters of ‘variety’ to form the word ‘cultivar’. A variety should be self perpetuating to some degree, and may be naturally occurring. A cultivar perpetuates by unnatural means, and would go extinct otherwise.

Of course, the distinction between variety and cultivar is not always so obvious. Varieties of nasturtium were selected from plants that displayed desirable qualities. Seed of these varieties grows into plants that display the same qualities. However, without continued selection, some varieties eventually revert to a more feral state in only a few generation. They are not truly self perpetuating.

Most hybrid tomatoes are unable to perpetuate themselves naturally. Their seed is either not viable, or is very genetically variable. Genetically variable seed grows into plants that are very unlikely to produce fruit that is comparable to that which produced their own seed. Nonetheless, hybrid tomatoes grown from original (primary generation) seed are generally varieties rather than cultivars.

The distinction might be that they grow from seed. A plant that is cloned rather than grown from seed is a cultivar. Cloned plants can be grown from cutting, layering or grafting onto understock, but are genetically identical to the original. Some rare camellias grown now are genetically identical copies of original cultivars that were developed centuries ago. Their seed would not be the same.

Some cultivars developed from selective breeding. Others were random but appealingly distinctive plants in the wild or even in landscapes. Many originated as ‘sports’, which are mutant growths of otherwise normal plants. For example, some plants, on rare occasion, produce stems with variegated foliage. Cuttings taken from such variegated stems became popular variegated cultivars.

Seed from a variegated cultivar is very unlikely to produce more variegated plants.

Posted on by tonytomeo · 4 Comments

Evergreen Trees Have Their Place

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Evergreens are sometimes the best choice.

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.

Posted on by tonytomeo · 6 Comments

Exotic Species Can Become Naturalized

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Naturalized Himalayan blackberry is detestably aggressive.

Every palm tree in local landscapes is exotic. Simply put, all palms are originally from somewhere else. The desert fan palm, the only palm that is native to California, came from isolated colonies in desert regions many miles away. In fact, most plants in common landscapes are exotic. Landscapes composed of Californian plants likely include some plants from other regions of California.

With few exceptions, exotic plants are not a problem. However, some of those few exceptions have become very serious problems. Himalayan blackberry, blue gum, silver wattle, pampas grass, giant reed and broom are some of the more notorious examples. They naturalized to become prolific and aggressively invasive weeds. Some are more common than natives in many situations.

Naturalized exotic plants such as these are problems for local ecosystems, even if they do not affect refined landscapes. They compete with native plant species for limited resources, space and pollinators. A lack of pathogens from their homelands can be a distinct advantage. They alter the lifestyles of some of the native fauna. Some enhance the combustibility of the forests they inhabit.

The justifications for importing exotic species are as varied as the species themselves are. It might have been for lumber, forage, fruit, or vegetable production. Giant reed might have arrived here as packing material for cargo from southern Asia. Nonetheless, most naturalized exotic species, including the most aggressively invasive, came here simply for home gardening and landscaping.

Realistically, of all the countless exotic species that came here during the past few centuries, very few naturalized. Fewer are now aggressively invasive. Some with potential to naturalize may not have yet been able to escape the urban situations they inhabit. The problem now is that there are so many more exotic species readily available from all over the World than there has ever been!

Online marketing facilitates procurement of exotic and potentially invasive plant species from other regions, with minimal regard to regulation of such commodities.

Posted on by tonytomeo

Variegated Foliage Brightens Shady Spots

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Variegation contrasts nicely with dark green.

Up at high elevations and out in deserts, where sunlight is most intense, plants can actually get more exposure than they need. The bluish or grayish glaucous foliage of the Colorado blue spruce from the Rocky Mountains, and the century plant from the Sonoran Desert, is actually designed to reflect a bit of sunlight so that the foliage does not scald.

Plants from foggy coastal areas, and understory plants that naturally live below the canopies of larger trees, do the opposite. They are deep green to absorb as much sunlight as possible. This is why Monterey pine and Monterey cypress are the same shade of dark green; and why most ferns are such dark green. Only tree ferns that stand above lower plants are naturally light green.

This can make it difficult to brighten a dark spot in the garden, since most lightly colored foliage wants an abundance of sunlight. White or lightly colored flowers would theoretically work nicely, but generally are neither permanent nor abundant where shaded. Golden foliage, like that of golden elderberries, golden arborvitaes and golden junipers, is greener in the shade.

Variegated foliage is different. Even if the green parts of the foliage are greener where well exposed than where shaded, the variegated parts are always variegated. Some plants are variegated with white. A few are variegated with yellow. Those that tolerate shade can brighten shaded spots nicely, or at least add a bit of contrast to dark green.

Even if the big pastel flowers of variegated angel’s trumpets and variegated hydrangeas do not stand out as well as they would against deeper green foliage, the foliage provides its own contrast. A concern with hydrangeas, as well as variegated dogwoods, is that they are deciduous, so lack foliage through winter.

Variegated Pittosporum tobira and variegated euonymus have smaller evergreen leaves. Variegated ivies are nice ground covers. On a smaller scale, so is dead nettle. Euonymus, pittosporums and ivies will sometimes need to have more vigorous unvariegated stems pruned out before they overwhelm and replace variegated growth.

 

Posted on by tonytomeo · 14 Comments

Deadhead To Eliminate Fading Bloom

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Deadhead finished daffodils to conserve resources.

The need to deadhead so early in spring is one of the few minor consequences of spring bulbs. Long before it becomes necessary to deadhead zinnia, canna and rose, the first flowers to bloom as winter ends are already finished. Many are those of spring bulbs. Their lingering deteriorating bloom can be slightly unappealing. What is more of a concern, is that some will likely try to go to seed.

The process of producing unwanted seed consumes resources that could otherwise sustain more useful growth. However, for spring bulbs that have finished blooming, production of seed for a new generation is more important than their own survival. That is why it is helpful to deadhead bulbs and many other plants after bloom. If deprived of seed production, they divert resources elsewhere.

Deadheaded narcissus, daffodil, freesia, lily and tulip store more resources into new bulbs, which they generate to bloom next year. Snowdrop and grape hyacinth cultivars that get deadheaded are not likely to get overwhelmed by their own feral seedlings. (It is neither practical nor necessary to deadhead crocus or big naturalized colonies of snowflake, feral snowdrop or feral grape hyacinth.)

While it is important to deadhead most spring bulbs after bloom, it is also important to not remove deteriorating foliage prematurely. After all, the foliage produces the resources that are necessary to generate healthy new bulbs for next year. Such foliage starts to slowly deteriorate immediately after bloom, but may linger for many months. Bulbs will shed their foliage when they no longer need it.

Until then, bedding plants or low perennials can obscure deteriorating bulb foliage as it falls over. Trailing gazania and dwarf periwinkle work nicely for shorter bulbs. If they get shorn low for winter, trailing plumbago, common periwinkle and African daisy can work nicely for taller bulbs.