As winter makes its arrival, most plant lovers turn their attention indoors. The bromeliads are a group of plants that lately have become more readily available in commerce. Most are durable and adapt quite well to indoor conditions. In all cases, they are characterized by foliage that usually grows as a rosette and often is vividly colored or patterned. Their colorful, exquisite flowers are unlike any other in the plant kingdom.
Named in honor of Swedish botanist Olaus Bromel, the Bromeliaceae, or pineapple, family of plants are mainly native to the tropical Americas. Some are terrestrial, while most are epiphytic in growth habit, taking root on tree branches in the understory of tropical rain forests. Since there are more than 3,500 species of bromeliads, most do not have common names. Instead, they are known by their genus designation such as Aechmea, Bilbergia, Guzmania, Neoregalia, Tillandsia and Vriesea. When common names exist, they often are very descriptive of the plant's appearance, such as scarlet star, tri-blushing, flaming sword and silver vase.
The bromeliads fill a very interesting ecological niche in the wild. An Ecuadorian study of 209 plants identified over 10,000 animals, representing more than 300 distinct species, associated with the plants examined. Many of the species are found only on bromeliads. Examples of species that reside in/on bromeliads include small salamanders, tree frogs and a species of crab. Some bromeliads in nature even form homes for other species of bromeliads.
As houseplants the bromeliads are not demanding and their attractive leaves give them continual interest. Leaves range in morphology from broad, flat and leathery to fine, soft and graceful, depending on genus. Most leaves have serrated margins that can be menacing to those unaware of their sharpness. Bromeliad leaves range in color from maroon, through shades of green, to gold. Some may have variegated leaves suffused with red, yellow, and/or white. Other bromeliads sport leaves spotted with purple, red, or cream; the bottom leaves of some are different in color from those at top.
Flowers, when produced, are very unusual and more diverse than any other family of plants. The inflorescence of most bromeliads take the form of elaborate and vividly-colored spikes enclosed in a colorful sheath and bract structure. This structure remains attractive long after the true flowers have faded giving the plant extended color. Bracts may survive and be attractive for several months up to a year, depending on species and environmental conditions.
Because many species of bromeliads are epiphytic in nature, they have the unique ability to trap and conserve water. The center of the rosette formed by a bromeliad's leaves is known as a "cup" or "vase." In nature, this cup fills every time it rains and serves as a source of water. Additionally, the cup collects insects and organic debris which, as they decay, serve as a source of nutrients for the plant.
For best indoor performance, bromeliads should be located in bright, diffused light. Those species with hard, thick leaves (e.g., Aechmea fasciata) can put up with brighter light compared with species that have soft, thin leaves (e.g., Tillandsia usneoides). A yellowish or pale green plant may indicate that the light level is too high. Conversely, dark green, soft, drooping leaves may be signs that light is too low. There are no bromeliad species that perform well indoors under poor light conditions.
In nature, ephiphytic bromeliads grow without soil, clinging to trees for support. Even the terrestrial types grow in rocky soils that hold very little water. Therefore, a well-drained growing medium is needed in order for bromeliads to thrive as indoor plants. Shredded bark, leaf mold or peat moss combined with bark, perlite, coarse sand or clay pot shards can provide the aeration and necessary drainage.
In the home, bromeliads need only light fertilization at monthly intervals when the plants are actively growing. Although they need constant moisture around their roots, excessive moisture encourages root rot. Keeping a bromeliad's cup full of water is considered by many to be a good cultural practice. However, do not put a fertilizer solution into the cup.
Bromeliads are not overly particular when it comes to temperature. Those temperatures maintained in the average home for human comfort will also suit most bromeliads. Although bromeliads prefer high humidity, those with thick, leathery leaves are tolerant of the lower humidity levels found in most indoor settings.
Fairly slow to propagate, bromeliads can either be grown from seeds or vegetatively propagated. The latter involves removing and rooting naturally occurring offshoots (pups). Because many of the more attractive species grow rather slowly, the initial cost of a bromeliad sometimes is higher than that of other indoor plants. However, their novelty and durability make them a worthwhile investment.
Some of the more popular bromeliads include silver vase (Aechmea fasciata), triblushing (Neoregelia carolinae 'Tricolor'), scarlet star (Guzmania lingulata) and flaming sword (Vriesea splendens). All are ephiphytic bromeliads that enjoy warm temperatures and are relatively easy to care for in the average home.
As mentioned previously, flowers are not common on bromeliads and are usually produced as the plant reaches the end of its life. Most nurseries that produce bromeliads force them into bloom to make them more attractive at the point-of-sale. This often is accomplished by exposing the plant to chemicals such as Ethephon which cause the plant's cells to release ethylene. The latter is a plant growth hormone which promotes senescence or biological aging.
The same tactic can be used to force bromeliads into bloom in the home using an apple. Place the plant in a clear plastic bag with no holes in it and add an apple. Apples naturally produce significant amounts of ethylene as they ripen. Allow the plant to remain in the sealed bag (with apple) for about a week or 10 days, making sure the plant is not exposed to excessive light while sealed inside the bag. Finally, remove the plant from the bag and place it in its normal location in the home. Depending on species, evidence of flower initiation should occur within about six weeks.
As mentioned above, an individual bromeliad plant flowers only once and then (slowly) dies. The flowering process will, however, encourage the plant to produce offsets as well. These offsets can be removed from the plant to propagate more bromeliads, or allowed to remain on the plant and induced to flower using the process described above.