Too much in the garden may be going to pot.

Container gardenin is overrated.

The class of 1985 epitomized the ‘Decade of Decadence’ with the raddest of styles in the wildest of colors. My generation is perhaps more familiar than any other with the pursuit of senseless fads and trends. Now that it is about a quarter of a century later, many of us continue such indulgences in our gardens.

Container gardening has become a fad that, despite its practicality for all sorts of applications, has become so common that it actually makes gardening more work than it should be. Modern homes are built with expansive porches and walkways that are designed to accommodate large urns and other planters, instead of more modest and proportionate porches and walkways that leave more space for planting things in the ground around them. Runoff from the planters stains pavement and rots decking. Besides, all the clutter of planters looks like a garage sale.

For balconies, roof gardens or wherever exposed soil is otherwise unavailable, container gardening may be the only option. Containers also help with plants that need to be moved to sheltered spots during frost. However, few plants are as happy in containers as they would be in the ground. Contrary to popular belief, it is better to amend inferior soil in the ground than to grow plants in potting soil within pots.

Where pots or other containers are necessary, they should either be shaded, or otherwise insulated from the heat of the sun. The black vinyl cans that plants arrive from the nursery in are not only unappealing, but can get warm enough in the sun to roast roots. Yet, they are both obscured and shaded simply by getting placed within slightly larger urns or planters.

Other thin plastic pots can transfer heat like black vinyl, but tend to be cooler because they are most often lighter colors that absorb less heat from sunlight. Thicker materials, such as terracotta, are better insulated. Roots prefer the porosity of unglazed pots, although some glazed pots can stay cooler. Plants within containers are often able to provide their own shade by cascading out over the edges, or spreading out above.

Yet, more substantial plants that provide more substantial shade still need to be complaisant to confinement. Plants that need to disperse their roots will never be comfortable in containers. Neither will plants that are not conducive to pruning, but want to grow into large shrubs or trees.

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Not All Plants Like Fads.

Ornate pots and planters can be as decorative as the plants within them, and provide extra accommodation for more plants.

Like so many fads too often are, container gardening is overrated, and is actually contrary to the currently most faddish of fads; sustainability. Plants in containers need more regular watering than those that can disperse their roots more extensively into the ground. Those that are so indulged also want fertilizer to be applied more regularly, but are more likely to be damaged if fertilized too generously. Because confinement is stressful, plants in containers are innately more susceptible to disease and pests. Some plants need more pruning for confinement.

Then there are the problems with the containers. If exposed to sunlight, thin plastic containers get warm enough to cook roots within. Pots that do not drain adequately or that sit in their own drainage basins can stay saturated enough to kill roots. Water in drainage basins allows mosquitoes to proliferate. Seepage from large pots can rot decks and stain pavement. Self watering containers work nicely for houseplants (if used properly!), but lack drainage, so can not be used out where they are exposed to rain.

The advantages to container gardening are actually quite limited. Containers are obviously needed for houseplants, and where exposed soil is not available, like on balconies. They are also convenient for plants that want better soil than they can get in the garden, especially if the rest of the garden is responsibly landscaped with sustainably undemanding plants that do not require soil amendment or regular watering. Frost sensitive plants can be moved easily to sheltered locations if contained. Flashy plants like orchids and tuberous begonias that get displayed prominently while blooming can be concealed while not so impressive.

Of course there are many pendulous plants like Boston fern, spider plant, string or pearls and burro’s tail that really are at their best in hanging pots. It is also hard to deny that there are all sorts of artsy containers, like colorfully glazed pots and sculptural concrete urns, which are appealing enough to justify growing plants in them, even if just to show off the fun containers. Bonsai requires containers, but that is another big topic!

Mexican Heather

Mexican heather has finely textured foliage.

The minute bright pink flowers of Mexican heather, Cuphea hyssopifolia, are less than a quarter inch long, but are enough to get the attention of the hummingbirds who really dig them. Flowers can rarely be more purplish or even more rarely white. The limber stems are well foliated with finely textured and narrow leaves that are not much more than half an inch long. Mature plants are typically lower but a bit wider than two feet. Overgrown plants can be pruned severely at the end of winter to regenerate over summer.

Some Plants Can Go To Pot.

What ever happened to those poinsettias and cyclamen from last Christmas?

Chrysanthemums, hydrangeas, azaleas, callas, kalanchoes and miniature roses can not really be as happy as they seem to be while in full bloom at the florist counter. Then there are all the seasonal blooming plants like Easter lilies and poinsettias. Wrapped in undraining mylar, often with ribbons and bows, they are actually quite humiliated.

All are forced to bloom in artificial greenhouse environments that are nothing like the home environments that they ultimately go to. As they finish bloom, most get retired directly to the garden where many are unable to adapt quickly and efficiently enough to survive for long. Many do not make it that far, but get sent to the compost or the trash by those who prefer to not prolong their agony.

These potted plants (which are actually known as ‘pot plants’ in the horticultural industries) are not like houseplants, since they are not actually expected to survive for long in the home. They are only expected to perform for a limited time while in bloom.

Adapting to the home environment is not the difficult part. Most potted plants can manage that for a while, but eventually want more sunlight. Hydrangeas, roses, Easter lilies and other deciduous plants also eventually want a cool winter for their dormancy. The problem is adapting to exposure to the sunlight and weather that these plants crave. Foliage can get scorched, frozen or desiccated.

As unsightly as plants can be during transition, most can eventually replace their greenhouse foliage with foliage that is adapted to their new environment in the garden if transitioned slowly and carefully. Large ‘forced’ flowers will eventually be shed or can be pruned off as they deteriorate. The more sensitive types of plants should be moved to a sheltered spot on a porch or in partial shade for a few months before being moved to more exposed spots. Once in the garden, they will want regular watering until their roots disperse.

Deciduous plants and bulbs can stay in the sheltered spot until they defoliate for winter. If put into their permanent location while dormant and bare, their new foliage that emerges in spring will be adapted to the new exposure.

Aloes, Christmas cactus and various other succulents are considerably more resilient and adaptable than the more common potted plants. Both rosemary and small olive trees that have become trendy during the past many years can likewise be adaptable if not kept in the home too long. Olive trees can stay potted indefinitely if pruned regularly, or can go into the garden where there is room to grow. Christmas trees are just as adaptable, but do not want to stay potted for long. Sadly though, most get much too big for home gardens.

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.

Gardening Up A Wall

These succulent tapestries exemplify artistic vertical gardening.

Like so many fads often do, the vertical gardening fad has become trendier than it really should be. It certainly has practical applications, and is very appealing in the right situations. However, in the wrong situations, it can be more problematic than it is worth.

Vertical gardens can shade and insulate exposed walls, but really do little more than strategically placed shade trees, large shrubbery or even trellised vines can do in that regard. The disadvantage of vertical gardening is that it can hold moisture against the affected walls, and can promote rot if the planters are not installed properly. Planters over windows or decks drip just like any other planters do, staining or dirtying whatever is below. Only free standing vertical gardens (that are not attached to a wall) or those on concrete walls that are not susceptible to rot will not cause such problems.

Water borne pathogens (diseases that disperse in water) can proliferate more in vertical gardens because they get carried with the natural flow of water from top to bottom. Wherever any such disease gets established on a vertical garden, it will likely get carried to everything below. In the ground, such diseases spread slower since they only travel as far as water flows or gets splashed.

The obvious advantage to vertical gardening is that it makes it possible to grow many more plants in very limited space, which is excellent if there is no open ground for vegetable gardening. It can also be a great way to display plants like orchids and certain bromeliads that are more appealing if they hang from above. Staghorn ferns cling to walls naturally.

Another advantage is that vertical gardening can be so aesthetically appealing and unique. Vertical gardens of small, densely foliated succulents hung like tapestries to adorn exterior walls are so much more interesting than simple vines or shrubbery used to obscure such walls. Northern exposures that are too dark for most plants can be adorned with ferns.

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.

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.

Not All Plants Like Fads.

Ornate pots and planters can be as decorative as the plants within them, and provide extra accommodation for more plants.

Like so many fads too often are, container gardening is overrated, and is actually contrary to the currently most faddish of fads; sustainability. Plants in containers need more regular watering than those that can disperse their roots more extensively into the ground. Those that are so indulged also want fertilizer to be applied more regularly, but are more likely to be damaged if fertilized too generously. Because confinement is stressful, plants in containers are innately more susceptible to disease and pests. Some plants need more pruning for confinement.

Then there are the problems with the containers. If exposed to sunlight, thin plastic containers get warm enough to cook roots within. Pots that do not drain adequately or that sit in their own drainage basins can stay saturated enough to kill roots. Water in drainage basins allows mosquitoes to proliferate. Seepage from large pots can rot decks and stain pavement. Self watering containers work nicely for houseplants (if used properly!), but lack drainage, so can not be used out where they are exposed to rain.

The advantages to container gardening are actually quite limited. Containers are obviously needed for houseplants, and where exposed soil is not available, like on balconies. They are also convenient for plants that want better soil than they can get in the garden, especially if the rest of the garden is responsibly landscaped with sustainably undemanding plants that do not require soil amendment or regular watering. Frost sensitive plants can be moved easily to sheltered locations if contained. Flashy plants like orchids and tuberous begonias that get displayed prominently while blooming can be concealed while not so impressive.

Of course there are many pendulous plants like Boston fern, spider plant, string or pearls and burro’s tail that really are at their best in hanging pots. It is also hard to deny that there are all sorts of artsy containers, like colorfully glazed pots and sculptural concrete urns, which are appealing enough to justify growing plants in them, even if just to show off the fun containers. Bonsai requires containers, but that is another big topic!

Drought Tolerance Versus Container Gardening

Drought tolerant plants loathe root confinement.

There are probably just as many reasons to not grow plants in containers as there are reasons to justify container gardening. Some potted plants consume less water than they would in the ground, but only because their demand is proportionate to their limited size. They only want more water in the ground because they can grow larger.

The most drought tolerant of plants are actually the least practical for pots or even large containers. They tolerate drought because they efficiently disperse their roots so extensively. Since they can not adequately disperse their roots in pots, they rely on what they can get from a relatively limited volume of soil. However, even if watered generously, many drought tolerant plants simply can not produce enough finely textured roots to absorb enough moisture.

For example, eucalyptus trees want to begin dispersing their roots while very young. If confined, their long and wiry roots simply go around within their limited volume of soil, trying to find a way out. They can develop a few more fibrous roots than they typically would, but probably not enough to compensate for limited root dispersion.

Wild lilac (Ceanothus spp.), flannel bush, manzanita and smoke tree are not only sensitive to confinement, but have difficulty recovering from confinement if put into the ground after their roots have circled too much within a container. Pines and many other conifers are likewise sensitive to confinement, but some types can recover if the binding roots get severed before they go into the ground.

Plants with dense and fibrous roots are more adaptable to containers. Most succulents and common yucca are good choices. Ferns and some grasses also work nicely, but need to be watered rather regularly. Some types of arborvitae and juniper work better than larger coniferous evergreens. Some small bamboos can stay potted, but not larger types.

Annuals, compact perennials and many ground covers that provide color and fill in space around larger plants are naturally adaptable to container gardening, but their need for regular watering can not be denied. There simply is no practical way of combining container gardening and drought tolerance.