The most familiar bromeliad, the pineapple (which is the fruit), gives you an idea of the basic plant shape. Most bromeliads have their leaves in a rosettes, like the top of a pineapple. The leaves may be thin and grass-like, or thick and succulent, and are variable in color. The ones favored by frogs generally have leaves that form tight cups at their bases which hold water, providing moisture and living quarters for our favorite amphibians. Frog vivariums limit the types of bromeliads that we can keep to those that are small enough, that can live in moist tropical conditions, and that do not have large spines that might be a danger to the frogs (or more likely, to the frog keepers!). Their suitability varies with the species and variety, and what they're used for in the vivarium.
Many plants that might be considered more suitable for vivarium conditions, but bromeliads are by no means difficult. The main concern is to give them enough light. All other conditions that we have supplied for the benefit of the frogs will suit most types of bromeliads just fine. The main potential problem with bromeliad culture in vivariums is that their roots should be kept from getting waterlogged as the plants can rot, but under certain conditions even this may not be a problem.
There are many ways of providing light for your terrarium plants, some of which may be rather expensive. There are high intensity halide lights that can almost duplicate bright sunlight, and special growlights that indoor gardeners use. Actually, almost any type of white fluorescent light will work, including regular hardware store types, as long as you have enough of them. Two standard 40-watt tubes, the kind sold as shoplights, are usually enough to grow most bromeliads if the distance of the plants from the lights isn’t too great. Tall vivariums will either need stronger lights, or more lights, or the bromeliads will have to be planted in the upper portions close to the lights. Be careful not to locate them too close to the lights, where they might be burned. Even fluorescent lights can burn leaves that come into contact with them for extended periods.
The leaves of a bromeliad can tell you what kind of light it prefers. Plants with hard, stiff leaves generally do better with more light, as do those that have leaves covered with gray scales or hairs. These plants can survive in lower light levels, but their leave will grow lanky and floppy and out of character, and their colors will fade. Bromeliads with soft, green leaves are more suitable for shaded areas, and can be use if lighting is limited.
In general, bromeliads like their root to be kept moist but not wet. They prefer to dry out a bit between waterings, so good drainage should be provided. Many bromeliads are epiphytes, growing on tree trunks and branches, or saxicolous, growing on rocks. These types are the ones that usually prefer dryer roots because that is what they have adapted to. Their roots may be simply wrapped in moss and tied to branches, where they will eventually attach themselves. If the substrate is well drained, they can also be directly planted into it. The advantage of attaching them to branches is that there is less chance, if any, of the roots rotting from too much moisture. Planting them on branches also allows the plants to be closer to the light source. Epiphtyically grown bromeliads often do not even use their roots to absorb nutrients; the roots serve only to hold the plants in place. As true air plants, they get all the nutrients they need through their leaves.
Some bromeliads are terrestrial, growing in soil like most other plants. Many can adapt to growing like epiphytes in a vivarium, but they often do better growing as they do in the wild, with their roots in the ground. These plants rely on their roots more than the epiphytes do, and their root systems is generally more extensive. Terrestrial bromeliads also can usually take more moisture than the epiphytic types.
It is often recommended that the water in their
central cups and leaf axils be changed by upended the plants and letting
the water drained out. This will prove impractical once the plants
are attached to branches or planted in the substrate. A solution
to this would be to pour or spray enough water into the leaves to rinse
out the cups. Do not do this too suddenly, because any tadpoles that
the frogs might have deposited in the cups may be flushed out. Spray
gently and simply allow excess water to drip out of the seams formed by
the leaf edges.
To keep the bromeliads from growing too big,
always provide them with the maximum amount of light that they can take,
and never fertilize them. The frogs will produce enough waste on their
leaves to keep the plants fed. A once weekly heavy misting is often
enough to keep them well watered. Good air circulation is always
a good idea and will also benefit the frogs as well.
Most bromeliads will only flower, but after
will form new rosette to replace the mother plant. Do not remove
the pups too soon; wait until they are at least a third the size of the
mother plant to give them a good start and so they have time to form their
own roots. To remove the pups use a serrated knife to cut away the young
plant as close to the mother plant as possible. Stoloniferous varieties
can be kept attached, producing a chandelier effect as more pups are produced.
Other types may look better grown as clumps, so it might be better to leave
the pups where they are, and simply pull out the mother plant's leaves
when they wither away.
Store-bought plants may have been treated
with pesticides, so always wash them well before putting them in the vivarium.
To be safe, the plants can be grown in a chemical-free environment for
a few months, and watered thoroughly to wash off the leaves. An even
better alternative is to grow the plants until they bloom and produce offsets,
and the offsets then used in the vivarium.
Unrooted offsets or pups are actually easier
to use, because they can be put in place without one having to worry about
any roots to cover. This is especially useful when mounting them
in an epiphytic situation; simply wrap the base of the pup with a bit of
sphagnum moss, and either jam the stem into a crevice in a branch or use
plastic covered wire or nylon fishing line to attach it. Small plants
may even be glued on, using a waterproof nontoxic glue. Hot glue
will work, as long as the glue isn't applied to where the roots are actually
growing from the base. When using hot glue, put a dab on an older
leaf sheath near the base, to avoid permanently damaging the plant.
Do not use bare metal with bromeliads, because these plants can react badly
to exposure to metals and may even die. If all other growing conditions
are maintained, the pup will quickly produce holdfast roots and attach
itself to the substrate.
Given the proper care, bromeliads can provide
you with a long lasting and hardy vivarium plants, lending that authentic
touch to your little chunk of the Neotropics.
Some bromeliads that you might use are:
- Aechmea Plants of this genus are among the most popular bromeliads seen for sale; the species most commonly available in the US is A. fasciata. This species is often seen in supermarkets, with its gray-green leaves sprinkled with white powdery scales, and its inflorescence composed of stiff pink bracts (flower spike). Its slightly spiny-edged leaves form a large watertight cup, perfect for a tadpole nursery. Another species which holds a lot of water is A. fulgens; this species carries red berries for a long time on its inflorescence. The variety discolor has wine red undersides to its leaves. Unfortunately, these plants are too large for most vivariums, reaching almost two feet across. Smaller species are A. gamosepala, which has round-ended leaves arranged in a rather tubular rosette, and lavander-blue berry-like flowers, and A. recurvarta and its varieties, which don't hold much water but are a sturdy and attractive contrast with their narrow pointed leaves. Aechmeas like bright light to maintain their firm leaf growth and they grow well epiphytically.
- Billbergia This is another kind of bromeliad that grows well in terrariums; they are especially hardy and fast growers. Queen's Tears, B. nutans, is an old favorite. Their flower stems don't last very long, but are attractive, often looking like they have pink or red streamers tied to their stalks. Leaves may be very attractively patterned. Billbergias don’t have many leaves per plant, but they can quickly form thick clumps. Several types can hold a lot of water, making them potential frog nurseries. Most varieties grow rather large like the Aechmeas, but some hybrids form very compact tubes that could fit in well in a vivarium. Bright lighting keeps them more compact, and maintains leaf color as well.
- Cryptanthus Popularly known as earth stars, they are popular vivarium plants due to their small size. Their leaves do not form water-holding cups, but are very attractively colored and patterned. They are mostly terrestrial plants, and do better planted in a well-draining substrate rather than as epiphytes. They also prefer bright light to maintain their colors. C. bivittatus has leaves with lengthwise stripes, sometimes pink or red depending on the variety. C. fosteranus and C. zonatus both have leaves with silvery crossbars on dark backgrounds.
- Guzmania are very popular houseplants because they can tolerate lower light levels than many other bromeliads. Their upright flower stems are brightly colored and very long lasting as well, and their soft leaves are spineless and perfectly safe for the frogs. G. lingulata and its many varieties make good terrarium plants because of their relatively compact stature. There are also many hybrids that are commonly available.
- Neoregelia These plants are very popular as well, with their brightly colored low-growing rosettes. N. carolinae is a popular houseplant in its variegated form, cv. tricolor, is very attractive with green leaves striped with white and tinged with pink. Like most Neoregelias, its central leaves turn bright red when it is in flower. N. cv. Fireball is a popular vivarium subject with dark burgundy leaves in good light, and numerous offsets or "pups" on short stolons. I have rooted this form in small cups of water showing how adaptable this plant is. It is a compact plant, but even smaller are N. ampullacea and N. tigrina, which look like little green test tubes with reddish spots and stripes. Neoregelias do not form flowering stems but produce their flowers directly in their central cups.
- Nidularium is a similar genus which also form low growing rosettes. Nidularims can tolerate low light levels and still grow well. They are mostly green, but the central leaves turn red when the plants are ready to flower, The brach forms a short stem and can lasts for several months adding a nice spot of color to your terrarium.
- Tillandsia Known as the airplants, they have the most varied growth forms among the bromeliads, ranging in the wide-leafed rosettes to whispy mosslike forms. The genus can be roughly divided into two groups based on their preferred growing conditions: mesic and xeric. The mesic species, like T. cyanea and T. complanata, prefer moist conditions, and can hold some water in their rosettes. Xeric species prefer dryer conditions and will die without good air circulation. Xeric species generally are characterized by slivery hairs or scales that cover their leaves, which the plants use to absorb atmospheric moisture. These hairs have to dry out between waterings, or the plant will suffocate. These forms count among the true air plants surviving and growing even without being firmly attached to anything at all. Tillandsias can be easily glued by their bases to branches, even upside-down. In fact, the inverted position can prevent xeric types from rotting by preventing water from collecting on their leaves. T. ionantha is a xeric species which does well in vivariums, and its little clumps of pointed green leaves turn red when the plant is flowering.
- Vriesea is another popular houseplant, and most species and hybrids do well in relatively low light levels like we find in our vivariums. Like Guzmanias their leaves are usually soft and spineless. V. splendens, with it's dark-striped green leaves and flaming red flower spike, is spectatular and often seen for sale in supermarket flower shops. Smaller varieties often have plain green leaves, but their paddle-shaped flower spikes always provide a long-lasting splash of color and makes them easily recognizable. Varieties such as 'Julie,' 'Mon Petit' and 'Pinkert' stay on the small side.
