Rubber Tree

Big glossy leaves of the familiar rubber tree like a sunny spot in the home, away from sources of heat.

Pruning a rubber tree, Ficus elastica, in the home takes a bit of acrobatics, since any wound immediately bleeds staining white latex. While pruning with one hand, the other hand must catch the latex with a rag. A third hand is needed to catch the bleeding piece of stem that gets pruned away. To make things more complicated, all three hands should avoid the potentially caustic latex. Even if it is harmless to the skin, it is a painful irritant if it gets into the eyes.

Young trees have larger glossy leaves that may be as long as a foot and half as broad, although most are about half as long and broad. Many modern cultivars have variegated or bronzy foliage. Where it gets enough sunlight as a houseplant, rubber tree will eventually need to be pruned for confinement. After all, in the wild, it can get more than a hundred feet tall and almost two hundred feet tall, with trunks more than six feet wide! In the garden, it needs shelter from frost. Aerial roots can develop in humid environments.

Air Layer Overgrown Houseplants.

Air layering big houseplants, like these lanky rubber trees, keeps them proportionate to limited space while also propagating new plants.

Most of the favorite houseplants are grown for dense evergreen foliage. Stems of Chinese evergreen, anthuriums, bromeliads and most ferns should never be seen. Yet, there are many houseplants that grow like small trees or coarse vines. Various ficus, dracaenas and philodendrons can get too big for their situations if not pruned. Palms can not be pruned down, so can only be moved or given to friends with higher ceilings.

Pruning and discarding overgrown but slowly growing stems seems like such a waste. Technically, stems from almost any overgrown houseplant can be rooted as cuttings. In reality though, most rot before they develop roots.

‘Air layering’ is probably the most efficient technique of propagation of houseplants from overgrown stems. It involves rooting the stems while still attached to the original plant. In the end, an unwanted stem gets pruned away as a freshly rooted new plant.

Air layering needs a bare and manageable section of stem that is at least a few inches long. This section does not necessarily need to be where the stem will eventually get pruned away from. It can be a bit higher (or farther out from the origin) if a shorter copy (new rooted plant) is desired. The extra length of stem in between can be pruned out when the copy gets separated.

The stem should be notched up to a third of the way through. This notch will develop roots better if rubbed with rooting hormone. A big wad of wrung out damp sphagnum moss a bit larger than a softball then gets wrapped around the notch, and then wrapped in plastic film. A cut up freezer bag should work nicely. The bag should be held in place with plant tie tape or something as simple as electrical tape, wrapped firmly around the stem above and below the sphagnum moss. Smaller stems can get smaller wads of sphagnum moss.

Unfortunately, there is no way to disguise the unappealing wrapped moss during the few months that may be needed for roots to develop. Eventually, roots become visible through the plastic, or the moss becomes firm with roots. The newly rooted stem can then be cut below the roots, unwrapped and potted as a new copy of the old houseplant. The stub below can be pruned away, or left to develop new shoots.

Poinsettia

After their distinctive and colorful bracts are gone, poinsettias can become handsome foliar houseplants or tall and lanky blooming shrubbery.

The tiny, yellow buds at the center of poinsettia (Euphorbia pulcherrima) blooms are actually the unimpressive flowers. The colorful red, white, pink or rarely pale orange bracts surrounding these flowers are merely colorful leaves. Some varieties have marbled, blotched or spotted bracts. Compact potted plants that are mostly less than two feet tall and broad can get quite lanky and taller than ten feet in the garden. The dark green leaves are about three to five inches long.

Chinese Evergreen

With such lush foliage, Chinese evergreen is a bold houseplant alone, and is also quite compatible with all other houseplants.

It is no coincidence that Chinese evergreen, Aglaonema, is perhaps the most common tropical plant for interiorscapes. It is quite easy to care for, and available in so many unique personalities. Many have rich deep green foliage. Most are elegantly variegated with white, silvery gray or gold. Leaf shape is quite variable, although most have rather narrow leaves radiating outward from dense rosettes. Leaves can be half a foot to more than a foot long, and a bit more than an inch to almost six inches wide. Mature plants are at least a foot tall and a foot and a half broad.

Indirect sun exposure or partial shade is best. Chinese evergreen likes humidity, so likes to share sheltered enclosed atriums with other lush foliage plants. New plants are easy to propagate by division.

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.

Burro’s Tail

Burro’s Tail is old fashioned, but can also be contemporary.

Back when big spider plants or Boston ferns suspended in fancy beaded macrame were all the rage through the 1970’s, burrow’s tail, Sedum morganianum, was an unusual but also trendy succulent perennial for sunny spots in the home or sheltered and slightly shaded spots in the garden. The refined foliar texture and light bluish green color contrasted nicely with the big and deep green leaves of comparably trendy philodendrons. The thin stems are too limber to stand up, but cascade excellently. Plants in the garden that get pruned back while dormant in winter can easily get two feet long through summer. Without pruning, big plants can get longer than six feet. Pruning scraps and even the small but plump leaves can be rooted and grown into new plants. It is impossible to prune or even move burro’s tail without dislodging some of the leaves anyway. Watering should be regular but not excessive, but then minimal for plants in the garden through winter.

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.

Angel Wing Begonia

Begonia involucrata at Monte Verde

The simple pink or sometimes red or white flowers of angel wing begonia are not as flashy as those of other begonias, and are not abundant enough to provide much color. During warm weather, they are merely a minor bonus to the striking foliage. As the name implies, the big and angularly lobed leaves are shaped like wings of angels. Upper surfaces are glossy and dark green with irregular silvery spots. Undersides are even glossier and reddish bronze. With support, the lanky cane stems can get more than twelve feet tall. However, because older tall canes produce runty foliage, they are often pruned out to promote more vigorous and lushly foliated young canes.

Because they are sensitive to frost, and also because they are ideal houseplants, angel wing begonias are typically grown in containers. They like rather regular but not excessive watering, and rich potting soil. Abundant sunlight enhances foliar color; but harsh exposure roasts foliage. Partial shade is not a problem.

Philodendron selloum

Philodendron selloum is unfamiliar with autumn.

There are all sorts of philodendrons with all sorts of fancy names. Yet, the biggest and boldest lacks a common name (at least one that is actually ‘common’), and is most popularly known by a Latin name that is not even correct. The proper name for Philodendron selloum is really Philodendron bipinnatifidum. It is a big awkward plant with big and deeply lobed leaves on long petioles (leaf stalks), and weirdly thick aerial roots. Well exposed plants can stand on wobbly trunks. Partly shaded plants can creep along the ground, and prefer to grab onto and climb tree trunks, fences or anything that they can get a hold of. The aerial roots are harmless to trees, and generally too slow to catch a healthy cat, but will take paint off of walls. All parts of Philodendron selloum are toxic.

String Of Pearls

Weird but elegantly pendulous string of pearls likes to hang around. It cascades nicely from hanging pots or tall urns.

It is difficult to see how string of pearls, Senecio rowleyanus, is related to much more colorful daisies and asters. The small, fuzzy and sickly white flowers are not much to look at, and only clutter the elegantly pendulous and oddly succulent foliage. The round leaves are light bluish green, so actually resemble peas more than they resemble pearls. The stems are so very thin and limber that they can only stand a few inches high, but can cascade to three feet!

Although evergreen, stems of outdoor plants can be cut back while dormant through winter to promote fresher growth in spring. The pruning scraps are very easy to propagate as cuttings. Roots are undemanding and sensitive to rot, so should be allowed to get nearly dry between watering. Bright ambient light without too much direct sun exposure is best. Incidentally, all parts of Senecio rowleyanus are toxic.