Cultivating Carnivorous Plants (2015)
BROMELIADS
Although it has long been theorized that
some bromeliads are carnivorous, only three
species - Brocchinia hechtioides, Brocchinia reducta,
and Catopsis berteroniana - are currently known to
be carnivorous. In time, more carnivorous
species will probably be discovered. Two of
these carnivorous species, Brocchinia hechtioides
and Brocchinia reducta, grow alongside Heliamphora
in the highlands of Brazil, Guyana, and
Venezuela.
The
other
species,
Catopsis
berteroniana, grows on bare tree branches from
southern Florida to southern Brazil.
The first real proof that any one of these
species was carnivorous came in 2005, when a
scientific study revealed that the long-held
theory that Brocchinia reducta was carnivorous was
correct. Prior to that year, it has long been
known that Brocchinia reducta, and the other two
carnivorous species, had specialized adaptations
that increase their ability to attract and digest
insect prey. These adaptations included not only
the ability to hold water, which almost all
bromeliads share, but also an ultraviolet-
reflective, waxy coating atop their bright yellow
leaves. Previous tests had shown that this
coating was similar to the waxy coating inside
Nepenthes or Sarracenia pitchers. Further, their
bright yellow leaves make them appear similar to
flowers, in the eyes of insects.
The leaves of the three species differ
somewhat. The leaves of Brocchinia reducta form a
Brocchinia reducta growing on the Gran Sabana of
tight, tubular rosette, creating a single water-
Venezuela, the habitat of some Heliamphora.3
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NATCH GREYES
storing cup. In contrast, the leaves of Catopsis berteroniana overlap in such a way as to create a series of water-
storing cups in the leaf axils. Finally, Brocchinia hechtioides has leaves intermediate between these two, creating
both a central water-storing cup and water-storing cups in the leaf axils.
In Cultivation
Brocchinia reducata in cultivation at the University of New Hampshire.
Brocchinia reducata in cultivation at the University of New Hampshire.
Brocchinia hechtioides, Brocchinia reducta, and Catopsis berteroniana are all fairly easy to cultivate and tolerate a
wide range of conditions. Therefore, it makes sense to speak of them in one cultivating section, despite their
diverse natural habitats.
All three species get most of their water and nutrient requirements from the water stored in the wells
created by their leaves. Very little uptake occurs via the roots. Therefore, unlike with other carnivorous plants,
growers need not be too concerned about media but only supplies of moisture. Specific requirements follow:
Brocchinia hechtioides
Brocchinia hechtioides grows terrestrially in nutrient-poor soils alongside Heliamphora and Brocchinia reducta.
Its leaves form a narrow rosette, allowing water to collect in both a central cup and in the leaf axils. As with
Brocchinia reducta, Brocchinia hechtioides prefers an environment that closely mimics that of the Tepuis (daytime
temperatures around 68° F (20° C) and nighttime temperatures around 45° F (20° C), but it will grow in
almost any conditions above freezing and below 95° F (35° C).
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CULTIVATING CARNIVOROUS PLANTS
Brocchinia reducta
Brocchinia reducta is the most studied of all the carnivorous
bromeliads. It grows terrestrially in nutrient-poor soils alongside
Heliamphora and Brocchinia hechtioides. Like many Tepui-dwellers, it
often grows atop the bare rock of the Tepuis. This rock is, more
often than not, Precambrian quartz arenite sandstone. It is
unknown whether the addition of sandstone to the potting
medium affects the growth of the plants, but, anecdotally, some
of the largest specimens of this species are at the University of
New Hampshire, where they grow atop sandstone.
The leaves of Brocchinia reducta overlap and create a tight,
tubular rosette, resulting in a single, water-storing cup. The tops
of the leaves are coated with loose, waxy scales, which easily flake
off under an insect’s foot. A sweet odor is emitted from the
center of the plant’s rosette, probably as a way to attract insects.
During the day, it experiences warm, windy, and humid
conditions. During the night, temperatures plummet.
In 2005, it was determined that Brocchinia reducta produces at
least one digestive enzyme, phosphatase. Although it is not yet
known whether Brocchinia hechtioides produces digestive enzymes,
the production of phosphatase, in combination with other
observations about the structure of the plant, suggests that
Brocchinia reducta is better adapted to carnivory than other species
of carnivorous bromeliads. Its tall, tubular rosette is narrow,
making it difficult for flying insects to escape. Additionally, its
waxy coating, which provides a poor foothold for insects, appears
slightly more apt at flaking underfoot than the waxy coating of
Brocchinia reducata in cultivation.
Brocchinia hechtioides and Catopsis berteroniana.
Catopsis berteroniana
Catopsis berteroniana is an epiphytic bromeliad. It grows in sunny locations, on
bare tree branches, anchored by a mass of wiry roots. In southern Florida, it has
been reported as occasionally growing atop telephone poles, although this is rare.
Like Brocchinia reducta, the digestive action of Catopsis berteroniana has been
extensively studied. This study revealed that Catopsis berteroniana depends on
bacterial action to digest the insects that fall into the plant’s water-filled axils as a
consequence of its flaking wax. Sessile glands on the plant’s leaves absorb the
nutrients of the digested prey.
The major difference between Catopsis berteroniana and the other carnivorous
bromeliads is that Catopsis berteroniana is an epiphyte. In cultivation, this does not
translate into any special difficulties, although its preference for growing on the
unshaded terminal branches of trees in the hot equatorial region indicates that this
species cannot be given too much sun.
Catopsis berteroniana4
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NATCH GREYES
My standard growing guide for carnivorous bromeliads is as follows:
✵
Media: An airy mixture of one part long-fiber sphagnum, one part perlite, one part orchid bark, and
one part tree-fern fiber works well, but any bromeliad mixture appears to work well.
✵
Moisture: Moist, but not wet, roots are ideal. Water should be kept in the wells of the carnivorous
bromeliad as much as possible.
✵
Humidity: Humidity should be kept relatively high for best growth, although all three species of
carnivorous bromeliads are tolerant of a wide range of humidity levels.
✵
Pot Size: Pots should be small. Their primary purpose is to anchor the plant.
✵
Feeding: An orchid fertilizer diluted to quarter strength and applied to the well appears to aid growth.
✵
Temperature: Temperatures should be kept above freezing and below 95° F (35° C) for all three
species. Brocchinia species are native to the Tepuis of South America and live alongside Heliamphora.
As a consequence, they tend to prefer cooler temperatures than Catopsis berteroniana.
✵
Dormancy: Dormancy is not required for carnivorous bromeliads.
✵
Propagation: The easiest way to propagate bromeliads is to wait for the parent plant to form pups.
This usually occurs after flowering, but it can occur at any time. After the pups have rooted, separate
them from the parent plant.
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