Care and Feeding of Carnivorous Plants


Introduction and Disclaimer

This is my culture sheet for the Carnivorous Plants that I grow. The techniques I describe are the ones that I use to keep my plants happy and alive. While I have had success with what I talk about here, I make no guarantees that what works in my situation will necessarily work in yours. There are also a number of techniques involving terrerium growing which I have not included, since at this time I am only just becoming familiar with them myself.

That said, I have divided the information here into categories of plant genera. If anyone wishes to update or correct anything I may state here, such commentary is more than welcome. Similarly, if anyone has any specific questions, I would be more than happy to do my best to get you a good answer.

In general, most Carnivorous Plants actually have quite simple needs. These needs, however, are different from those of other types of plants, and as such, may be counterintuitive for those with previous experience growing plants.

These needs are:

Water

CP's like water, and lots of it. Most CP's grow in bogs or other very wet environments. In cultivation, most CPs do best with purified water. I use a commercially available reverse-osmosis (RO) purifier, or distilled water would make an acceptable substitute. Water from charcoal filters is better than the tap water in most locations, but as your collection grows, it's worth investing in a good purifier.

Light

At home in the bogs, there are very few obstructions to sunlight. As such, most CPs require a great deal of light to thrive. A south or west-facing windowsill is usually adequate. If sunlight isn't available in sufficient quantity, I've had very good luck with twin-tube flourescent shop light fixtures. Some people claim that expensive grow-light tubes are worth the money. I'm on a budget, so I couldn't justify a twenty-dollar tube over a two dollar tube. In any case, keep them within 6-12 inches (15-30cm) of your plants' leaves.

Growing Medium (soil)

Most CPs developed the carnivorous habit due to the highly impoverished soils in which they live. Since they were unable to absorb nutrients through their roots, they evolved a method by which nutrients could be absorbed from the environment. As such, regular, commercially avilable potting soils which contain high concentrations of nutrients will severely burn the roots of most CPs, causing a quick death. The growing medium of choice is usually a mixture of peat moss and sand. This combination is acidic, and contains very little of nutritional value. Peat moss is also able to hold several times its own mass in water, so it will keep your plants properly wet. With the exception of some species of Nepenthes, plant food, fertilizers, or other nutritional supplements will prove lethal unless severely diluted. I don't use any of these at all, and have had good luck. If you do use them, make sure to try it out on a single plant before you subject your entire collection to a potentially deadly treatment.


Cephalotus (Western Austrailian Pitcher)

Growing Medium:

I've had good luck growing Cephalotus in a mixture of peat moss, sand, and perlite (1 part perlite, 1 part sand, to 2 parts peat). I grow mine in a 4"(10cm) square pot. Generally, shallower, wider pots tend to promote a greater number of crowns from this plant. The roots can't go as far down, so they grow outward, producing new shoots all the way.

Water:

Cephalotus requires somewhat less water than, for example, Sarracenia. During the winter, I leave mine sitting on a plastic plate, and on a daily basis pour on purified water until I can see it seeping out through the bottom of the pot onto the plate. During the summer, I water by the tray method, as for Sarracenia.

Light:

In full sunlight, Cephalotus turns a deep purple color, but produces slightly smaller pitchers. Conversely, in more shaded environments, the plant produces larger, green pitchers. One trick I have used with some success has been to keep the plant in a shadier spot until the pitchers have reached a nice size, then place the plant in a sunnier spot. In this way, you get the large pitchers, along with the deep color. In any case, Cephalotus will require at a minimum an hour or so of direct sunlight, or several hours of indirect light each day. A bright windowsill works nicely. For artifical light, a photoperiod of around 12-14 hours works well.

General:

I have only grown Cephalotus in trays and in pots, although it is an ideal terrarium subject. In such a rarefied environment, the plant is certain to grow quite vigorously. Cephalotus does not require a period of dormancy, but if you intend to grow it in the open air (indoors or out), it will need slightly different treatment in the colder seasons. Fungus is a problem, so when it is colder, keep it less moist (although definitely do not let the growing medium dry out!). The advice I was given along with my first plant was "Water this one less than the other pitchers". This has held me in good stead, and should you too.

Darlingtonia (Cobra Lilly)

Growing Medium:

I use the same mixture for Darlingtonia as I do for Sarracenia, 3 parts peat moss to one part silica sand or perlite. Larger containers help to keep the roots cool, which this species likes. Larger pots also allow for stolons to form, and produce new plantlets.

Water:

Use only purified water for Darlingtonia. The tray system is fine, as with Sarracenia, but, since the plant naturally occurs around coastal streams and mountain runoffs, the roots need to be kept cool. Growers have had good luck keeping 2-liter soda bottles in the freezer, then setting them in the water trays with the plants. I have never done this, but it does seem reasonable. Another alternative is to use a small aquarium pump to keep water circulating, but this requires growing the plant essentially hydroponically.

Light:

Darlingtonia seems to burn easily in full sunlight, so some shade or shadecloth is in order. Flourescent light works well also. In any case, a photoperiod of roughly 12-14 hours during the summer, tapering to as little as 8 hours in the winter should produce good results.

General:

I have to admit, my success rate with Darlingtonia is the lowest of any genera of CP. Whether this is due to starting with inferior product, or simply my own inability to make this plant happy, I don't know. In any case, it is certainly a gorgeous plant when healthy, so i will keep trying!

Dionaea (Venus Flytrap)

Growing Medium:

Grow Dionaea in a mixture of 3 parts sphagnum peat moss to 1 part silica sand. Use a 4"(10cm) pot for a standard-sized plant. In these conditions, you will get a very healthy plant that will produce a large number of leaves on relatively long stalks. Strangely enough, I have found that keeping the plants in a 2"(5cm) pot, while reducing the number of leaves the plant will produce, results in much larger traps on short stalks. I have no idea why this would be, perhaps being root-bound somehow inspires the plant to grow bigger traps.

Water:

Water Dionaea using the tray system, as described above for Drosera. Use pots with drainage holes in the bottom, and keep them standing in a tray filled 1-2 inches(2-5cm) deep with water. As with Drosera, overwatering is not a concern. I have heard reports from people who have observed that in its natural habitat, Dionaea sometimes spends as much as several weeks submerged during the wet season.

For individual pots, yogurt or salsa containers, once properly cleaned, make excellent, if not entirely decorative watering trays.

Light:

Dionaea likes it bright. In full sun, the traps will develop a lovely red hue. In my experience, however, more than about 6 hours of direct sunlight produces very small leaves. To keep the plants ahppy and attractive, keep them thoroughly watered, and if you are in a dry climate, keep them indoors. If you're using artificial light, keep the photoperiod around 14 hours during the summer, stepping down to around 10 hours during the winter.

General:

Dionaea really does not deserve its reputation as a plant that does little else than die. This is doubtless caused by faulty growing instructions, and a basic misunderstanding of what the plant actually needs. The leaves can snap shut and re-open many times over the life of the leaf, but it robs the plant of potential food whenever it happens. While this is not in any way catastrophic to the plant, it's nevertheless a good practice not to let the kids snap all the traps shut. Save it for a special occasion!


Drosera (Sundews)

I grow several species of non-tuberous Drosera, from a number of parts of the world. Most species are cultivated in the same way, with exceptions made for those species which require a winter dormancy period. Those species and their specific requirements are included in a table at the end of this section. Please bear in mind that the tips here are for non-tuberous Drosera. Since I haven't yet made any attempt to grow tuberous Sundews, I actually have no idea how to go about doing so.

In general, Sundews are very easy plants to grow, and are thus ideal for beginners.

Growing Medium:

Grow Drosera in 3 parts sphagnum peat moss to 1 part silica sand (both are available at home and garden stores). Use either plastic pots or glazed ceramic. In any case, make sure the pots have drainage holes in the bottom. For most species, a 4"(10cm) pot is sufficient.

Water:

Water by the tray system: Place pots in a tray of water. Try to keep the water level between 1-2 inches(2-5cm), although keeping the level consistent is more important than what the level actually is. The plants will absorb water through the drainage holes at the bottom of their pots, and the peat/sand mixture will remain saturated. Do not worry about overwatering sundews.

For individual pots, yogurt or salsa containers, once properly cleaned, make excellent, if not entirely decorative watering trays.

Light:

As long as your sundews remain in standing water, the challenge will be in providing sufficient light for your plants. I have found it very difficult to over-sun my plants as long as they stay in standing water. A south or west-facing windowsill will work nicely. Most sundews like at least 4 hours of direct sunlight per day. If this is a problem, consider a flourescent light fixture.

General:

Sundews are pretty easy plants: Keep 'em standing in water, put 'em in the sunniest window in your house, and, aside from some admiration, ignore 'em, and they'll do just fine!

Dormancy Requirements for Drosera Species

Species

Dormancy Requirement

Notes

D. binata and D. binata dichotoma 1-2 months If left in a windowsill, plants will go into dormancy without additional action. In artificial light, shorten the photoperiod to 8-12 hours
D. intermedia 2-4 months (Same as above)

Other species, such as D. rotundifolia will require longer dormancy periods, but at the moment, I am not growing them.


Nepenthes (Tropical Pitcher Plants)

Growing Medium:

Nepenthes enjoy well-drained growing media. Other growers have had luck with media such as bark chips or sphagnum moss. Personally, I have had the best luck with a substance called "Rockwool", a spun-mineral material that resembles fiberglass insulation. It is sold either in loose bales, or packed into various sized cubes. The disadvantage to this material is that a rooted plant cannot be easily removed to rinse the roots. I also have one plant, purchased commercially, which is packed in a medium of peat moss and bark, and it has done fine. The trick is to keep the roots moist, but not so wet that they experience root rot. Depending on the size of the plant, you'll need between a 2"(5cm) pot or Rockwool cube, and a 10"(25cm) pot, or perhaps even larger.

Water:

Water Nepenthes from above, and let the excess water drain away. I have also had good luck using a small spray bottle, misting the leaves at least once daily. Unlike many other plants, Nepenthes do not "live in their roots", which means that the leaves must be kept healthy in addition to the roots.

Light:

Most Nepenthes grow in habitats close to the equator, where the length of days varies very little with seasonal variation. As such, Nepenthes are not adapted to do anything particular when the length of their photoperiod changes. The plants that I have do not respond well to direct sunlight, getting a little cooked. A soft filter, indirect light (but lots of it), or a venetian blind closed almost completely to strong sunlight should do the trick. Of course, flourescent tubes would also do nicely. In this case, you can use almost any photoperiod, although I wouldn't recommend less than 12 hours. For establishing young plants, I have used up to a 24 hour photoperiod for up to 3 weeks, and the plants seem to enjoy it.

General:

While most Nepenthes can be grown in a bright spot in a house or apartment, a greenhouse or terrarium will generally give better results. Additionally, plants from lower elevations (lowland species) prefer a warmer, tropical climate, while species which grow at higher altitudes (highland species) like the air a little cooler. In my experience, the crucial temperature concern with Nepenthes is a significant difference between the daytime and nighttime temperatures. Individual species have their own particular likes and dislikes, but what I have mentioned here has generally worked for all of my plants.


Pinguicula (Butterwort)

Growing Medium:

I grow Pinguicula in a mixture of 50% peat moss and 50% silica sand. Other growers have suggested a medium of pure perlite, which should also work fine, although I haven't tried it. Species forming winter resting buds should be removed from the medium and refrigerated (assuming the roots, as well as the leaves die back). Homophyllous and heterophyllous types can be left in trays year round, but keep the water level slightly lower in cooler temperatures to avoid rot.

Water:

Water by the tray system: Place pots in a tray of water. Try to keep the water level between 1-2 inches(2-5cm), although keeping the level consistent is more important than what the level actually is. The plants will absorb water through the drainage holes at the bottom of their pots, and the peat/sand mixture will remain saturated.

Light:

I have found that most Pinguicula like it a bit less bright than, say Drosera. A spot in a greenhouse or windowsill which is bright but doesn't get much direct sunlight works well. Flourescent light is also a good option.

General:

Most evergreen Butterworts are quite easy to grow, and are quite rewarding to cultivate. They are ideal for apartment dwellers, or others for whom space is at a premium. I treat mine essentially the same as I do Drosera, with the exception of placing them in a slightly less sunny position. Their flowers are also quite lovely, and provide a very nice decorative presence.

Sarracenia (Trumpet Pitcher Plants)

I grow nearly all species of trumpet pitchers, which are native to the Southeastern U.S. All species require a winter dormancy period, which will be discussed at the end of the section. For this reason, many people find it more enjoyable to grow trumpets along with some evergreens, such as sundews or Nepenthes.

Trumpet pitchers, like sundews, are also easy to grow, although they are slightly more challenging.

Growing Medium:

Grow Sarracenia in 3 parts sphagnum peat moss to 1 part silica sand or perlite (both are available at home and garden stores). Alternatively, live sphagnum moss may be used. A word of caution: many garden centers sell what they believe is sphagnum. Often this is actualy some other form of decorative moss which will not support your plants. Unless you really know it's sphagnum, peat moss is safer. Use either plastic pots or glazed ceramic. In any case, make sure the pots have drainage holes in the bottom. For the S. rubra subspecies, a 4"(10cm) pot will be sufficient, but for the larger species, 6-8"(15-20cm) pots will give the plants the room they need.

Water:

Water by the tray system: Place pots in a tray of water. Try to keep the water level between 1-2 inches(2-5cm), although keeping the level consistent is more important than what the level actually is. The plants will absorb water through the drainage holes at the bottom of their pots, and the peat/sand mixture will remain saturated. During the growing season, it is impossible to overwater trumpets, although caution should be taken to keep the growing area well-ventillated to discourage mold growth during the winter. During this period, the water level can be lowered significantly. As soon as new growth appears, however, return the water level to its higher point.

Light:

Trumpet pitchers love a lot of light, 4 hours sunlight per day minimum. To keep the edges of the pitcher tops from burning, a shade cloth or semi-closed venetian blind may be used. This is unnecessary in areas where sunlight is less intense. If you are using artificial light, keep the photoperiod up around 14-15 hours per day during the active growing season.

General:

During the growing season, trumpet pitchers are extremely beautiful and satisfying plants to grow, although all require a dormancy period during the winter. If the plants are kept in a windowsill, lowering temperatures and a shortening photoperiod will cause the plants to go dormant at the right time. If you are growing under artificial light, shorten the photoperiod to around 8 hours per day to induce dormancy. Species from warmer areas tend to go dormant last and recover first (S. flava, S. leucophylla), while species from colder or mountain climes will have a longer dormancy period(S. purpurea,S. rubra jonesii). If a plant seems to die during the late fall, do not throw it out, this is normal! During dormancy, the pitchers will start to look quite bad, and in some species the entire plant will die back to the surface of the growing medium. In the spring, new leaves will begin to grow. It is advisable to keep the plants neatly pruned, and remove dead pitchers as soon as they lose their green.


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This page copyright 1997 by Michael Zenner. Last modified 4/2/98