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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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 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).

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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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.