Information on Carnivorous Plants
Since it was first observed and described in the western world, the capture and digestion of small animals by plants (carnivorism) has fascinated mankind. At first carnivorism was considered a distortion of normal plant life, but as over 400 naturally occurring species were identified it became clear that it is a normal, even common fact of plant life.
Carnivorous plants survive by photosynthesis, as all green plants do. They do not exist solely by “eating” insects; they employ insect food as a supplement to the nutrients available in the soil. They are generally opportunistic, thriving in wet, nutrient poor soils where competition from other plants is minimal. There are also exceptions: Nepenthes, the vining Asian pitcher plants, climb through the branches of tropical rainforests; theDrosophyllum of Morocco inhabits sandy, semi-arid hills. Whatever their habitats, carnivorism gives all of these”‘plants a distinct advantage in the struggle for survival.
Amateur cultivation of carnivorous plants (CP) has long been limited by three factors: the lack of literature for amateurs, the expensive facilities needed to grow CP, and a scarcity of sources for good and varied stock. However, more literature on this subject is becoming available, the technology of greenhouse, indoor and light gardening has advanced rapidly in recent years, making it easier and less expensive for amateurs to cultivate carnivores.
The “exotic” aspect of our native CP and their popularity as classroom items has led to unfortunate commercial exploitation. Hundreds of thousands of Venus’s Fly Traps, and thousands of Sundews and Pitcher Plants (including Darlingtonia) are sold annually, and allot of these plants is still collected from its natural habitat. As is also the case with many Orchids, Bromeliads, and Cacti, this commercial predation has forced many rare species to the brink of extinction, and it is driving others closer by the year. We at Hungry plants are the first carnivorous plant dealer and CP Nursery in South Africa to offer only commercially propagated plants. As some CP are rather slow to grow, it will be some time before we can offer commercially propagated plants of rarer Carnivorous Plant species. We hope that by propagating native plants and simultaneously opening a new market for foreign species we can reduce the demand for collected stock and the consequent burden placed upon wild populations. Propagated plants are a better value than collected stock in terms of price, quality, positive identification, and consistent freedom from pests.
WHY GROW CP?
CP are uniquely beautiful and bizarre, and amply rewarding to grow. CP terrarium make ideal mini-environments for classroom study, illustrating the interrelationships of living things and their environments. * The mystery of CP evolution and the remaining questions about CP physiology beckon the curious naturalist. How did they become what they are, and how do they work? The visual richness of the plants is a challenge to the creative photographer. And though they are fun to grow, more like pets than house plants, they will not rid your home of flies or cockroaches.
In order to avoid confusion we have used the accepted Latin names for each species, hybrid or variety of plant in the following sections. Some of these plants have been given common names, some have not. Those that have in some instances share their name with other species (i.e. “Pink Sundew” or “Spathulate-leaved Sundew”); some have more than one name, as does Drosera filiformis, called “Tall Sundew,”
“Thread-leaved Sundew,” and “Dewthreads.”
As for pronunciation, we all make mistakes on this, and chances are you won’t have much reason to discussUtricularia nephrophylla with anyone who won’t know what you’re trying’ to say. If you read the word carefully and phonetically you will come close enough. If you don’t want to bother, call it a Bladderwort. We do suggest labelling all of your plants with their proper names for future reference.
The sizes of leaves, etc., are given in metric units
centimeters and millimeters. 10 centimeters is roughly equal to 4 inches. If you are not familiar with these units, we suggest getting a ruler with metric demarcations to have handy when trying to visualize the size
or shape of a particular plant.
Genus DROSERA, The Sundews
The beauty and variety of the 100 or so Drosera varieties could well overshadow their unique adaptation to carnivorism. Charles Darwin described them as “a wonderful plant, or a most sagacious animal.”
Sundew leaf shapes range from slender threads to broad paddles to elaborate sprays resembling deer antlers. The leaves bear numerous tentacles which radiate in all directions. Each tentacle tip bears glands which secrete characteristic droplets of mucilage, giving the plant its dewy appearance. Insects are attracted by the look and smell of the leaves and become mired in the sticky “dew.” The struggling victim stimulates the tentacles to bend and touch it, drawing it closer to the leaf. At the same time glands in the leaf secrete digestive juices in anticipation of dinner. Large insects will often stimulate the entire leaf to curl, roll up or even fold over to bring more of the leaf surface into contact with its prey.
Sundews display different kinds of leaf motion.
While Drosera filiformis leaves don’t move, the leaves
of D. rontundifolia may curl up from the sides or tip, or both. D. capensis is very responsive. Its long leaves do not incurl sideways, but along their length, the leaf apex bending toward the leaf stem. It may fold over at the tip or fully in half, or roll.
Once we dropped a small worm-like larva on the end of a D. capensis leaf. Some hours later the leaf had rolled up its entire length in pursuit of its wriggly meal. The last three tentacles at the leaf base had finally pinned their quarry. Such a process may take hours.
Sundews grow well in CP mix (see How to Grow CP), or in peat or sphagnum moss (live or dried),
provided they have ample moisture, humidity, and drainage. These factors produce luxuriant “dewdrops.” Good light causes reddening of the tentacles; more gives the entire plant a crimson hue. While growing, Sundews produce a succession of leaves. Old leaves will eventually brown and decay, and they can be removed if you so desire. New leaves will take their places.
Sundews grown in glass containers allow maximum close viewing at different angles, which highlights the sparkling dewdrops. The effect under a hand magnifying lens is sensational. These and larger plants can be grown in combination so their contrasting shapes and dewy appearance produce displays of unearthly beauty.
Most healthy Sundews bloom in spring. Each flower opens only once for a few hours in the morning. A day or so later the next one opens, then the next. Unless you want to collect the seed that follows, snip off the flower stalk to save the plant’s energy for foliage growth.
Drosera adelae: Tropical; Australia; a beautiful rosette of semi-upright lance-shaped leaves up to 17 cm. long. Each leaf has a distinct central vein. A relatively difficult Sundew, not recommended for beginners. Prefers sphagnum and good drainage.
Drosera aliciae: Temperate; South Africa; a handsome rosette of wedge-shaped leaves, this Sundew resembles a hairy red pie sliced in even pieces. A slow but easy grower reaching 6cm diameter. Enjoys well drained peaty soil or live sphagnum, which will grow upward around the plant.
Drosera binata: Temperate: Australia and New Zealand; one of the largest and most striking of Sundews, with long, slender leaf stalks and twin leaf halves forming a delicate upright crescent.
Each leaf may be over 20 cm long and measure 12 cm between tips. Very easy to grow in sphagnum, it enjoys having its root tips constantly wet. Leaves are unable to stand erect if grown in low light. This Sundew will die back dramatically in winter and stay dormant for 3 or 4 months.
D. binata var. dichotoma: Temperate; sames as D. binata but larger, and the leaves divide a second time to produce four points. Easy.
D. binata var. multifida: Tropical; a large D. binata variety. The leaves split several times, producing numerous leaf points. A specimen of 40 points has been reported. Grows well in sphagnum and can be grown in a ‘hanging pot or basket in the greenhouse for a stunning effect. Easy.
Drosera burmanni: Tropical; Asia and Australia; a truly hardy Sundew which endures a wide range of soil and weather conditions. Grows as a distinct rosette of short, wide, blunt leaves with long tentacles. Plants grow to 4 cm diam. Two varieties -Taiwan and Hong Kong; the latter is smaller and develops more red coloration. Both are easy to grow, preferring wetness with good drainage.
Drosera x californica: hybrid (D. filiformis x D. filiformis var. tracyi) offering the size and hardiness of D. filiformis var. tracyi with the coloration ofD. filiformis (see below).
Drosera capensis: Temperate; South Africa; a plant of unusually impressive size and growth habit, its long, flat, oar-shaped leaves radiate from an upright stem. Plants grow 14-16 cm high with leaves up to 10 cm long. Easy to grow in sphagnum or CP mix, preferring the former. Keep root tips wet.
D. capensis narrow-leaf: looks Iike and is grown the same as D. capensis, but has narrower leaves reaching 21 cm long. Mature specimens will grow 18 cm tall and happily occupy a gallon container. This is a truly amazing Sundew, large, colorful, and easy to grow, if you have the space.
Drosera capillaris: Temperate; from Virginia south through Central and northern South America; this is a dependable, colorful Sundew. Several varieties grow between 2 and 6 cm diam. Prostrate rosettes with slightly egg-shaped leaf blades. Easy to grow in CP mix or other media.
Drosera filiformis: North Temperate; Eastern Coastal Plain from Massachusetts to North Carolina; distinct upright thread-like leaves up to 16 cm long uncurl from a central point. This plant must have good drainage. It is a bit fussy, slowing down or dying in insufficient light or over wet soil. It will form distinct winter buds to carry through dormancy.
D. Filiformis var. tracyi: Temperate; Southern Gulf and Atlantic Coastal Plain; the larger variety of D. filiform is, with leaves reaching 50 cm, though typically 35 cm or less, without red pigmentation. Much easier to grow -use CP mix or peat and keep roots wet.
Drosera intermedia: North Temperate; Europe, North America, Guiana; these are upright rosettes of slender stems with narrow spathulate leaves 5-7 cm long overall. I t grows in compact clumps during the first year, then grows an upright stem the second year, particularly if grown wet. Forms distinct winter buds. Easy to grow, and surprisingly large and beautiful when mature. Not fussy about planting medium.
Drosera montana: Tropical; Brazil and Venezuela; a small, attractive Sundew with white flowers. Typically forms rosettes 2 cm diam., though sometimes larger. Leaves are slender and tapered. Easy to grow.
Drosera x nagamoto: hybrid (D. anglica x D. spathulata),’ a very vigorous, dependable performer with rounded egg-shaped leaf blades sporting profuse tentacles. Semi-upright rosettes up to 7 cm diam., leaves 6 cm long. Sterile (no seed). Very easy.
Drosera, pygmies: Drosera pygmaea, D. pulchella, among other Australian pygmy Sundews. Besides
being tiny, some produce disproportionately large flowers, some do not bloom at all; many produce gemmae
round “buds” -during winter which produce new individual plants in the spring. Culture varies; most are
relatively easy to grow with standard Drosera cuIture.
Drosera rotundifolia: North Temperate; Northern Hemisphere; the best known of Sundews, it grows as a dense
rosette of very round leaves on stalks. Usually less than 5 cm. in diam., older plants in lower light may reach 12
cm diam. Grows in CP mix or other media, and should not be overly wet except in brightest sun. Forms distinct
winter buds. Easy to grow.
D. rotundifolia x D. intermedia: A large hybrid of the two northern Drosera, with wide leaf blades on long upright stalks. Grows easily 6 cm tall. An easy plant to grow, and an outstanding specimen. Grow the same as D. rotundifolia.
Genus UTRICULARIA, the Bladderworts
Bladderworts are” delicate rootless plants inhabiting stagnant ponds, bogs, and damp peaty soils. Their trapping mechanism is among the most intricate devices of the plant world.
Tiny egg-shaped “bladders” occur allover the underwater and underground portions of the plants. Each bladder has a delicate trigger hair extending away from the base of a watertight “door.” By pumping water out of the bladder while the door is sealed a negative pressure is created. Small animals brush the trigger hairs as they pass, forcing the door open. The pressure of the surrounding water forces the door open further and the animal is sucked in. If it traps something longer than it can “swallow” at once, the trap pumps the water out again and sucks in another piece, repeating the process until it engulfs the entire body. Bladderworts prey on a wide variety of small aquatic fauna.
Bladderwort flowers are exceptionally beautiful. Some terrestrial bladderworts are cultivated for their flowers alone. Most produce a fine moss-like mat of foliage, though some leaves grow 3 cm long or longer. At varying times, usually spring and summer, they are highlighted by yellow, purple or white flowers on tall stalks, They are easily grown in pots or terraria in CP mix, or in peat or sphagnum. They are a fine complement to aDrosera planting; even if lost in a growth of moss their flowers rise above it for a dramatic show of color.
Aquatic bladderworts are often free-floating or partially anchored networks of threadlike branches (or foliage, one can’t be sure) which produce flowers in season on stalks rising above the water’s surface.
They can be grown in still water in any glass container with a layer of soil on the bottom to provide nutrition. They can be fed very dilute fertilizer during the growing season. They require several hours of direct sun to flourish and bloom. During the winter northern varieties will form winter buds (turions) which should be allowed a period of 5 degree (C) temperature, reduced light and moisture, or refrigeration.
Utricularia dusenii: (also called U. nephrophylla); Tropical; Brazil; a slow-growing terrestrial bladderwort producing wide leaves 2 cm across and growing to 5 cm high. Prefers sphagnum.
Utricularia fibrosa: Temperate; Eastern US, an easy to grow aquatic bladderwort which produces several branches radiating from a central point. From the same point a flower stalk arises bearing several yellow flowers.
Utricularia juncea: Temperate; Easte”rn US; a prolific terrestrial bladderwort which spreads rapidly through CP mix, peat or sphagnum. Produces a moss-like mat of bright green leaves less than 4 mm long. Numerous tiny yellow flowers grow on stalks several cm high.
Utricularia prehensilis: Sub-tropical; Africa; an easy terrestrial bladderwort to grow. I t forms a dense mat of creeping grass-like leaves 3 mm wide and 2 cm long. Yellow flowers. This plant grows best at about 20 degrees C., though it will withstand cold.
Genus Byblis, the Rainbow Plant
The two species of Byblis are truly unique. The leaves are long and threadlike, radiating in all directions from a central stem. Numerous flowers are borne on stalks arising from the points where leaves and stem meet. The entire plant -leaves, stem, flower stalk -is covered with a dense coat of shimmering tentacles, similar to but finer than those of Drosera. Only’ the flower itself is devoid of protection. Overall, the plant is a pale gray-green color.
The name is derived from the Roman legend of Byblis, a niece of the Sun, who shed so many tears that she turned into a water fountain. Byblis gigantea is called the “rainbow plant,” for its tentacles refract sunlight in its many component colors.
The species linaflora means flax-flowered, for its blue flowers. It could just as easily be called the rainbow plant. These two are the only members of the Byblis family, and both are found in Australia.
This plant can be grown all year though it wiII grow too heavy for the stem to support, at which point it can be cut
off, the top rooted in planting mix and the base left to produce new shoots. I n nature it appears to be an annual,
setting seed, then dying at the end of the growing season. 8. /inaf/ora will grow in a mixture of peat and
sphagnum and perlite in a container with a deep layer of gravel, perl ite or other crocking, as it must have good
drainage. Provide good Iight and warmth.
HOW TO GROW CARNIVOROUS PLANTS
These plants have gone to great lengths to evolve their means of survival, and given the proper conditions they will eagerly take full advantage of them to grow and’!. flourish. Their needs are not hard to meet, but they are exacting.
SOIL: Most carnivores enjoy acid media like sphagnum moss and peat moss (which is decayed sphagnum). Sand may be added to either moss or both, or live sphagnum can be used. We prepare an all purpose CP mix of peat, milled dried sphagnum, and sand in the proportions 3: 2: 1. This is used for terrarium planting or covered with a layer of milled sphagnum for seedling germination. Some plants prefer a lighter mix with better drainage and aeration, which would contain equal parts of each ingredient.
For clay, plastic or glass pots or containers with drainage holes we use straight peat or long strand sphagnum. There are different useful media, but these principles must be followed: provide enough sphagnum or peat to retain plenty of moisture; allow enough drainage to prevent stagnation and rot of medium; don’t use any soil, leaf mold or loam unless recommended by an experienced CP grower; don’t use perlite or vermiculite, again unless recommended.
Most commercial milled sphagnum contains enough spores to sprout and grow, often with attractive results. Peat will also sprout a variety of weeds. It is usually not necessary to sterilize dried sphagnum.
When planting CP, soak the planting medium thoroughly, then squeeze out excess water. Place plants firmly in soil and water gently. For the first two weeks protect them from direct sun and keep very humid.
LIGHT: CP grow in open spaces, enjoying unobstruced sunlight part or all of the day. Direct sunlight or a first-rate substitute is essential. Strong light creates compact growth and good coloration well as encouraging flowering and seed production.
Plants should have at least one and preferably two or more hours of direct sun daily, with as much indirect light as possible. Less light results in scrawny foliage and lack of pigmentation. Incandescent lamps are only valuable as supplements, as they throw off too much heat in proportion to their total light output.
Carnivores will grow under fluorescent light alone. The pink or bluish lamps marketed as plant lights by various companies are adequate, but we prefer the new full-spectrum lamps such as Terrarium lite, which provide a more natural spectrum and a higher light output. They render colors more accurately as well, a big advantage in display lighting.
A fixture with reflector incorporating two 40 watt lamps provides ample growing space. Most CP will thrive with their top leaves between 10 and 30 cm below the center of the two tubes. Ideally, the closer the better, but taller plants present a problem, especially when blooming. For these set up flexible staging which can be raised and lowered as needed.
A single fluorescent lamp by itself is inadequate, but for less than ideal window light a lamp providing supplemental lighting will make the difference between average and good growth. A day length of 16-18 hours is usually enough. In late fall a shortened day length will coax plants into dormancy, which can be maintained with an 8-10 hour day and lowered temperatures.
WATER: CP need constant moisture and humidity. Plants in pots must be watered and misted frequently. They thrive under humid greenhouse conditions; in the home humidity must be provided by standing pots in.
The need for humidity can not be overemphasized for some species like Nepenthes.Tap water in some areas is too alkaline for C.P.. Rain, distilled and deionized water are safest, and the latter two are available at most pharmacies. Use tap water if you like, but be prepared. Salts may collect in the soil and sweeten it too much, making it necessary to replant frequently with fresh soil. We suggest replanting annually anyway, in early spring, as the organic soil components will decay in time.
CP UNDER GLASS: Fish tanks, goldfish bowls, glass jars and terraria make ideal homes for CP.. They retain humidity which promotes lush growth, as well as being pretty display pieces. An entire collection of Sundews; Bladderworts and Byblis can be housed in a ten gallon aquarium, or a few small Sundews will grace a fine glass bubble. Except for their flower stalks, these plants will not outgrow their containers but rather flourish within them.
A windowsill with 2 or more hours of direct sun in the morning or afternoon is a fine spot for a jar of Sundews, or they can be grown and displayed under fluorescent lamps (Plant lights). Care must be taken to prevent overheating by too much direct sun, and occasional ventilation provided to prevent mildew.
To plant a container, sprinkle a layer of gravel or other drainage material on the bottom.. Then create a landscape with CP mix and cover with a sprinkling of sand or milled sphagnum and plant.Add colored stones or sand and cover. Or put a potted plant in a covered jar, or a plant in a mound of live sphagnum.
FEEDING: CP are quite capable of surviving without being fed. They can attract and capture their own food, or they can be hand fed. Most eat small insects, though the larger Drosera can handle house flies with ease. If hand feeding, capture bugs which will not overtax the plant, and don’t overfeed; a few small insects a month during the growing season will be plenty. Do not use hamburger or other mammal meat as the plants will not be able to digest it. Large insects or meat will sit and rot, ruining the leaf.
Fertilizers are are not recommended as it will certainly kill the plants, so if in doubt, don’t.
FLOWERS: The best preparation for good flowering is proper care of the plant. When buds appear on weak or newly transplanted specimens, snip them off to save the plant’s energy. Failure to set buds or seeds is usually due to a lack of light, humidity, or both. It is recommended to remove the flower stalk as soon as it appears to save the plants energy if no seed is needed.
DORMANCY: All plants are accustomed to some seasonal change. We have identified each variety in this catalog according to the climate and geographical area it inhabits, and from that you can plan on how best to duplicate the necessary changes. We suggest growing climatic types together, especially if in group plantings.
Tropical: Excellent for indoor or tropical greenhouse culture, as they will grow almost all year. Should be kept at temperatures between 20 and 30 degrees C for best growth. Some kinds will tolerate temperatures close to freezing, but shouldn’t be expected to.
Temperate, Subtropical: Good for indoor and greenhouse culture, requiring a mild winter simulation (not below 5 deg. C) and slightly less water. Growing temperatures are the same as for tropicals.
North Temperate: Excellent for northern greenhouses with cold winters, also indoors. These require a dormant period of three or more months to thrive and flower more than one year. Some, such as D. rotundifolia, will not usually flower until after the first winter. Most North Temperate types form winter buds in response to lower temperatures and shorter days of less intense light. For uninterrupted rest, these plants should have winter temperatures of 1- 5 degrees C. When winter buds are fully formed, plants can be safely wrapped in moist (not wet) sphagnum and refrigerated (Cool not freezing)
PROBLEMS: Most trouble can be traced to one or more of the basic cultural elements
-moisture, humidity, light, acid soil, drainage and ventilation. First, re-examine the growing conditions. Perhaps the soil has become alkaline (litmus or soil test kit will indicate this), or the humidity may be too low.
Milled sphagnum and sand help prevent mildew, but at times a fungicide may be necessary. Pests are rare but do occur. Fungus gnats are common but are usually no more than a good source of plant food.
The following publications and links are suggested as sources of further information on CP. Also cunsult your school and public libraries for books. We hope you will enjoy growing these miracles of nature, the carnivorous plants.
Copyright 2015 by Hungry Plants, South Africa.
All Rights Reserved.