Tropical plants make a smooth transition as houseplants

Houseplants live outside somewhere.

Hibiscus, bougainvilleas, philodendrons and so many of the tropical and subtropical plants that we can enjoy in our gardens can only survive through winter in greenhouses in most other climates in America. Many of our tropical houseplants though, seem to be the same everywhere. Houseplants are generally grown in our homes not because they can not survive in our gardens, but because they ‘can’ survive in our homes.

Yes, houseplants are merely any plants, tropical or otherwise, that we grow in our houses. Yet, most and perhaps almost all of the plants that are best adapted to surviving as houseplants happen to be tropical plants. Tropicals do not need the seasons that they would get outside. Because many are native to dense and very competitive tropical forest environments, they are adapted to the sort of shade that they get in our homes, and survive on minimal volumes of soil that they have available while potted.

Nonetheless, they miss their tropical lifestyles. They only tolerate dry interior air, but would prefer more humidity. They would likewise prefer to be rinsed of dust more often than they can be in indoors. A regular supply of fresh organic debris to supply nutrients would be nice. However, if merely fertilized instead, tropicals are sensitive to salts and other toxins that eventually accumulate in the soil.

This is why some of the more resilient houseplants like to be brought outside for a gentle rinsing during a mild rain. As long as it is not too cool or windy, gentle rain rinses dust from the foliage and toxins from the soil. Plants can be brought out in the morning and brought in late to get as much time out in the rain as possible, but should not be left out overnight when it may get too cool. Even though they do not need any more moisture, plants can be watered by hose a few times to allow water to rinse freely through the soil.

Plants in overly decomposed potting soil are easier to repot with fresh soil while they are outside. Those that do not need to be repotted might still like getting grungy and potentially toxic mineral deposits scrubbed from their pots and drainage pans.

Christmas Trees Dead Or Alive

Live Christmas trees can get huge.

Poinsettias, Christmas cacti, cyclamen, various forced bulbs and several other seasonal potted plants are again becoming popular. It happens annually prior to Christmas. Heath, heather, rosemary, English holly with berries, and delightful compact conifers have been gaining popularity for many past years. Seasonal potted plants are increasingly diverse.

Unfortunately, few survive for long after Christmas. Forced bulbs exhaust their resources. Cyclamen are likely to rot after a month or so. Very few retire to a garden. Poinsettia gets too lanky in the garden to be a favorite. Most seasonal plants simply succumb to neglect. After their primary performances, they are no longer interesting enough to justify tending.

In reality, some of these seasonal potted plants are little more than cut flowers with roots. These roots allow them to live longer than cut flowers, but their ultimate fate is the same. Wreaths, garlands and various seasonal cut greenery likewise serve a purpose, but only temporarily. Without roots, it all lacks any potential to retire into a garden after Christmas.

Christmas trees are really not much different. Although there are several different sorts of Christmas trees, they fit into similar categories as cut foliage and seasonal potted plants. Obviously, they are seasonal. They need not last much longer than Christmas. Although, some have a potential to do so, few survive or function for more than a few Christmases.

Contrary to popular belief, and their expense, cut Christmas trees are generally the most practical Christmas trees. They are essentially a very substantial sort of cut foliage. They grow on farms like any other foliage and vegetables. After such a tree serves its purpose, it resigns to compost or green waste recyclery. A freshly cut tree can replace it next year.

Large potted Christmas trees may seem to be more practical, but require maintenance to remain as appealing as they are now for another year. Despite the expense, few last that long. They want to get out of confinement, so that they can grow as trees. Pre-decorated small trees are Italian stone pines. They grow much too big for contained home gardens.

Potted Plants Need Work Too

Most potted plants would prefer to be in the ground, . . . if possible.

Potted plants can be a problem any time of the year. Some want more water than get. Most get too much water or do not drain adequately. Large plants get constricted roots if pots are too small. The roots of some plants get cooked in exposed pots that collect too much heat from sunlight. Besides, too many pots just seem to be in the way in otherwise useful spaces on decks, patios and anywhere else trendsetting landscape designers want to put them.

Now that the weather is getting cool and rainy, potted plants are not as active as they were during warm weather. Many are dormant. Although few demand the attention that they got during warmer weather, plants still need to be tended to appropriately through autumn and winter.

Cool season annuals, which are also known as ‘winter’ annuals, should get groomed as long as they are performing in the garden, just like warm season annuals get groomed through summer. Deteriorating flowers should be plucked from pansy, viola, primrose, Iceland poppy, calendula, dianthus, stock, chrysanthemum and cyclamen because they can mildew and spread mildew to developing flowers and foliage. Unplucked cyclamen and calendula can develop seed which diverts resources from bloom.

Pots that are out in exposed areas will not need to be watered while they get enough water from rain. The problem is that many that do not drain adequately can get too much water from rain and stay saturated. Dormant and defoliated plants do not need much moisture at all. Even evergreen plants do not need as much as they do while active during warm weather, because cool and humid weather inhibits evapotranspiration (evaporation from foliar surfaces).

Potted plants under eaves also need less water while the weather is cool and humid, but need to be watered nonetheless because they are sheltered from rain. Plants in hanging pots typically drain and dry more efficiently, so probably want a bit more water. Even a few sheltered small plants in the ground may occasionally want to be watered during rainy weather if they do not extend enough roots where they can get moisture from rain beyond the sheltered area. Sheltered plants are actually the most likely to be neglected because watering does not seem so important when it is raining.

Chimney Clearance Must Be Maintained

Modern homes lack old fashioned fireplaces.

Even as autumn weather cools, smoke rising from a simple old fashioned brick chimney is a rare sight nowadays. A smoking stovepipe is rarer. Modern building codes forbid the installation of new fireplaces or wood stoves within most municipalities here. Modern air quality ordinances severely limit the use of existing fireplaces and wood burning stoves.

Furthermore, existing fireplaces and wood stoves are neither as popular nor as common as they had been. After an earthquake, a faulty chimney is likely to justify removal rather than repair. An unused wood stove wastes too much space. Old orchards that generated inexpensive firewood as they relinquished their space to urban development are extinct.

There are a few advantages to these modern trends though. Modern homes consume so much less energy for heating than older homes because of efficient insulation. Insulation of older homes retains heat that fireplaces generate, so that less wood is needed. Almost every surviving chimney has a spark arrestor. Modern roof materials are noncombustible.

Nonetheless, vegetation that gets too near to a chimney that is in use can be hazardous. Even if clearance was adequate last winter, trees, vines and large shrubbery grew since then. It does not take long for such vegetation to overwhelm a chimney, or encroach a bit more than it should. It does not take too much vegetation to be hazardously combustible.

Clinging vines like English ivy and Boston ivy sometimes climb up and then over the top of a chimney. Although not especially combustible, they will burn directly over a fireplace or wood stove. Just like gutters do, vines can accumulate leaves that fall from deciduous trees to become more combustible. Birds or rodents can build combustible nests in them.

Evergreen trees and big shrubbery are similarly combustible over a chimney. Deciduous trees are generally not as hazardous. Conversely, cypress, pine, cedar, eucalyptus, large junipers, and ungroomed palms are very combustible. Eucalyptus foliage will burn while fresh, if it gets hot enough. The other trees tend to accumulate very combustible detritus.

Dormancy And Defoliation Are Advantageous

Hostas go dormant and defoliate for winter, and regenerate for spring.

Many plants are deciduous in autumn and winter, which means that they defoliate or die back, and then refoliate or regenerate in spring. Many others are evergreen, which simply means that they are always foliated through all seasons. What many people do not realize is that evergreen plants replace their foliage just like deciduous plants do. They just do not do it in such distinct phases of defoliation, dormancy and refoliation.

Tropical plants like cannas and some of the various begonias really have no need for formal defoliation, since they are from climates that lack winter. In the wild, they continually and systematically shed old stems as they produce new stems. Locally, they tend to shed more than they grow during late autumn and winter. The large types of begonias tend to keep their canes for so many years that it is not so obvious. Where winters are colder, cannas freeze to the ground, only to regenerate from their thick rhizomes as winter ends.

Zonal geraniums may seem rather tired this time of year for the opposite reason. They expect late autumn weather to include frost that would kill them back to the ground where they would stay relatively dormant until warmer weather after winter. Just because their foliage is instead evergreen through winter does not mean that it should be. It lingers and often becomes infested with mildew and rust (fungal diseases) that proliferate in humid autumn weather.

However, zonal geraniums need not be pruned back just yet. Even if they eventually get damaged by frost, pruning should be delayed so that the already damaged older foliage and stems can shelter the even more sensitive new growth as it emerges below. They can get cut back after frost would be likely.

Evergreen pear can get very spotty once the warm weather runs out because the same damp and cool weather that inhibits its growth also promotes proliferation of the blight that damages and discolors the foliage. The damaged foliage eventually gets replaced as new foliage emerges in spring, but will remain spotty and discolored until then. Photinia does not get as spotty, but holds blighted foliage longer into the following summer. Ivy can be temporarily damaged by a visually similar blight.

Dried Floral Material Worth Recycling

Yucca bloom produces interesting floral stalks.

Gardens might be colorful throughout the year here. There is not much time between the latest of the autumn flowers and the earliest of the spring flowers. Winter flowers are glad to compensate for the lapse. Of course, there are plenty of flowers in spring and summer. Nonetheless, dried flowers are more popular now that there are fewer flowers for cutting.

The quantity of flowers blooming within a particular season might not be proportionate to the quantity of flowers available for cutting. Flowers that bloom through winter, even if as abundant as spring or summer flowers, do not develop as fast. Harvesting too many bird of Paradise flowers depletes the limited supply before something else can replace them.

Deciduous foliage that provides spectacular color through autumn is no substitute for cut flowers. Nor is the majority of colorful bark that becomes more prominent through winter. Some colorful berries can function like cut flowers, but only if there are plenty to spare in the garden. Conventional dried flowers that grew last summer may be useful about now.

For the venturesome and resourceful, unconventional dried flowers and other dried plant parts can also be fun. Such items, unlike statice, straw flower, lavender and other familiar dried flowers, might be byproducts of gardening. They might be derived from detritus that should otherwise go to compost or greenwaste. Some might even be products of weeds!

Pampas grass, both garden varieties and the invasively naturalized type, produces bold blooms that dry quite well. Because the leaves can cause such nasty paper cuts, flowers might be easier to harvest from a distance, with a pole pruner. Hair spray can contain the fuzz, so that it does not disperse indoors. Cat tails, if still intact, are compatible with them. 

Floral stems of lily of the Nile, New Zealand flax, and some species of Yucca are striking even after bloom. After deadheading, they can become flowerless dried flowers. Fruiting structures are no problem to remove. If within reach, some palms may provide distinctive bloom trusses. Floral design can be as imaginative as gardening and landscape design. 

Dried Flowers Last All Year

With proper processing, hydrangea bloom can be dried.

Statice, strawflower and globe thistle continue to bloom later than most other summer annuals, and hold their flowers longer. Even after bloom, the flowers are so stiff and ‘crispy’ that they remain intact and colorful until they succumb to exposure to weather. If cut and brought in from the weather soon enough, they will last as dried flowers at least until fresh flowers start to bloom in the garden next spring.

Strawflower and larger globe thistle tend to wilt and droop from the weight of the bulky flowers, so should be tied in small bunches and hung upside down to dry. Perennial statice (which has larger blooms than annual statice) tends to flop to the ground, but the stems often bend only at the base so that the rest of the stem length stays somewhat straight. Smaller globe thistle and annual statice often dry standing up while still out in the garden.

Yarrow and English lavender can be dried as well, but lose most of their color. Lavender dries naturally in the garden. Yarrow can likewise be allowed to dry in the garden, but probably keeps a bit more color if cut while still fresh and hung upside down. Because yarrow blooms are so wide, they should be hung individually or in small bundles. Queen Anne’s lace has even wider blooms that curl inward as they dry, so they really should be hung individually.

Old hydrangea flowers that are only beginning to fade can dry surprisingly well if cut and hung individually before they deteriorate too much or start to rot. Some varieties retain color better than others. Some fade almost completely to an appealing brown paper bag.

There are not many roses this time of year, but when they do bloom, even they can be cut and dried while beginning to unfurl. Only a few small and tightly budded roses can be dried when completely open. Because they droop right below the blooms, roses should be hung upside down to dry. Dark colored roses get very dark as they dry. White roses turn tan. Pink and yellow are probably the better colors.

Cat-tails and pampas grass flowers are big, bold and dated cut flowers. Yet, for situations where big flowers fit, they are just as practical now as they were in the 1970s. Because pampas grass flowers shed, and cat-tails can explode (to disperse their seed), they should be sprayed with hair spray or another fixative to keep them contained. Pampas grass foliage has dangerously serrate edges that can give nasty paper cuts, so should be handled carefully, and displayed out of the way.

Evergreen Tendencies Are No Mistake

Evergreen foliage is resilient through winter.

Evergreen plants retain foliage throughout the year. Deciduous plants defoliate for part of the year. That is the simplest explanation. The various reasons for shedding or retaining foliage are not so simple. Annual plants die after their single growing seasons. They can not live long enough to be either evergreen or deciduous. Some plants just may be both.

Foliar color, to some extent, conforms to preferable environments. Monterey cypress and Monterey pine have richly deep green foliage. It maximizes absorption of sunlight within the foggy coastal regions that the trees inhabit. Blue spruce has glaucous bluish foliage. It reflects a bit of sunlight to protect from sun scald within severe high mountain climates.

Similarly, deciduous plants generally defoliate for environmental situations. Most go bare for winter, in order to be less susceptible to damage from wind and snow. Bare stems do not collect as much heavy snow as foliated growth. They are also less resistant to wintry winds. If foliated, they are more likely to succumb to wind or overburdening snow weight. 

Evergreen plants may retain their foliage because they are from climates in which winter weather is not so harsh. Wind may be no more extreme than it is in other seasons. Snow may never occur. Plants from tropical regions may be unfamiliar with colder weather and shorter daylength associated with winter. Their evergreen foliage might function all year.

Some tropical plants that are evergreen within their native environments may defoliate or die back as a result of even mild frost. Some recover as if deciduous. (Those that can not survive local climate conditions are not very popular here.) For example, canna die back to the ground after frost, but regenerate later. In tropical climates, they can be evergreen.

Evergreen species from mountainous regions or extreme northern latitudes are generally uncommon here. They prefer harsher weather. Although evergreen, they are remarkably resilient to wind and snow in the wild. They are likely evergreen to always stay receptive to limited sunlight whenever it is available, though wintry weather is possible at any time. 

Many Perennials Want Seasonal Grooming

Where frost is not a major concern, old canna foliage can be cut back as new growth develops.

Here on the west coast, autumn and winter weather is so mild that the native coral bells are already starting to develop new foliage on top of the old foliage from this last year. Technically, they are evergreen, so the old foliage does not need to be shed; but if it is not too much to ask, some types look better with a bit of grooming.

Other perennial plants that are from climates with stronger seasons and colder winters are not quite so evergreen. Many shed all of their foliage and are completely bare for at least part of the winter. Only a few, like cyclamen, are at their best through autumn and winter.

Dried watsonia foliage should be removed now if it has not been removed already. It is not so easy to pluck off like gladiola foliage is, so it should be cut off with shears. Because new foliage for next year develops before the old foliage of this past year is completely brown, it is often necessary to cut the old a few inches above the ground in order to avoid damaging the new.

The so called ‘evergreen’ daylilies can be even messier. New foliage is rather delicate, so it is easily tattered by the removal of old foliage. The ‘deciduous’ types may seem to be less appealing because they are bare for part of autumn and winter, but are so much easier to groom by simply removing all of the deteriorating old foliage as soon as it separates easily from the roots.

Deteriorating flowers can be removed from cannas; but their lush foliage can stay until it starts to deteriorate later in winter. Even if it survives winter, it should eventually be cut to the ground as it gets replaced by new growth in spring.

The many different iris have many different personalities. Most should be groomed sometime between summer and late autumn, although Dutch iris were groomed much earlier. Bearded iris that do not get divided can be groomed simply by plucking off big old leaves to expose smaller new shoots below.

Some dahlias bloom until they get frosted. Most though, are already finished. They do not need to be cut back all at once, but can be cut back in phases as leaves and stems dry and turn brown.

ISA Certified Arborists Know Trees

Arborists work with the big trees.

Arborists are horticulturists. They just happen to be more specialized than most. Many or most other horticulturists work with flora that they engage from the ground. Arborists work exclusively with trees. Some must leave the ground to do so. The most experienced and educated arborists are those certified by the International Society of Arboriculture or ISA. 

ISA certification requires an arborist to pass an examination of arboricultural proficiency. Continued participation with ISA endorsed classes, workshops or seminars is necessary to maintain certification afterward. Arboricultural industries are demanding, with stringent professional standards. Certification with such industries is correspondingly demanding.

General information about the International Society of Arboriculture is available online at isa-arbor.com. This site, although designed for arboricultural professionals, is informative also for those who must procure the services of an arborist. The directory of ISA certified arborists can identify local arborists, as well as the tree services with which they affiliate.

Although arboriculture is pertinent throughout the year, it seems to become more so with the first storms of autumn. Some trees prefer dormant pruning during winter. Others might perform best after summer pruning. Various trees have various preferences. Regardless, the need for arboriculture becomes apparent as weather breaks limbs and uproots trees.

Trees are innately the most substantial and relatively permanent plants in home gardens and landscapes. Unlike annuals and some perennials, trees are not disposable, or easy to remove if they become too problematic. Many eventually get too big for those who are not experienced arborists to engage. That is why too many trees need professional help. 

Many municipalities require permits for the removal of significant trees. Inspection by ISA certified arborists, and associated reports, are generally prerequisites for the issuance of these removal permits. Some municipalities are more protective of trees than others. ISA certified arborists try to be familiar with the ordinances of the various municipalities in which they work.