Thumbnail guidelines on growing a tropical pitcher plant

• 
  Nepenthes ×superba
  (lower pitcher)
• Nepenthes ×superba
  (upper pitcher)

So, you have a Nepenthes, huh? Not quite my recommendation as a first carnivorous plant for the beginner to try. The challenge is that these plants can be really big, and so require really large growing areas. They don't usually tuck into a small terrarium very conveniently.

Let me suppose that you bought a small plant. By small, I mean a plant that occupies about as much area as your hand, with your fingers splayed. In this case, growing the plant is pretty easy. Unlike most carnivorous plants, Nepenthes do not require super bright light. So it might actually survive on a very bright windowsill. But it does like the light it would get from a bright terrarium, so don't hesitate to consider rigging up a carnivorous plant terrarium as I describe elsewhere in the FAQ. Even a bottle terrarium will be helpful if your plant is small enough.

Nepenthes plants do not like to be sitting in water, so put your little potted plant in a shallow saucer and water it every day or so---however often you find it necessary to keep the potting medium moist. If you keep it sitting in water, the root system will become dwarfed (at least for most species) and the plant will be small in general. They like conditions humid and warm. Never give them a winter dormancy, as they are tropical plants that grow year-round. If you must transplant them, put them in a mix like 50:50 Sphagnum:perlite.

Nepenthes like very high humidity, around 70-100%, so you'll need to keep it in some kind of humidity enclosure like one of the terrarium options I mentioned above.

If, for some fool reason, you have yourself a very large plant, you're going to have a devil of a time finding a place you can keep it. It will need lots of light, and plenty of humidity. Follow the same guidelines as for small plants---don't let it sit in water, but keep the soil moist. How you're going to achieve all this in a conventional house, I don't know. You really need a greenhouse.

If you try growing Nepenthes, but don't do it very well, the plant will probably survive fairly well, but might just look like a lanky vine. The pitchers the plant had when you bought it will eventually die, and the new leaves that form won't make replacement pitchers. This is very frustrating, I know. What must you do to have a plant make pitchers? Just grow the dang thing better. Pitcherless leaves, by itself, is such a general symptom that it can't be used to diagnose exactly what you're doing wrong.

If you have a Nepenthes plant and really want it to grow, I recommend you buy a book like D'Amato. That will cover all the extra stuff like fertilizing, propagation, etc.

Finally, if for some reason you have a hair up your bum to grow Nepenthes rajah as your first plant, take a pill or something. This is a very expensive plant with particular needs, and is suitable only for the expert.

What do you mean by "absorption pathways?"

• 
  Sarracenia
  purpurea
• Pinguicula
  primuliflora
• Utricularia
  dimorphantha
• Drosera
  glanduligera

This is the third attribute of a carnivorous plant:

A pathway is available that allows nutrients to be absorbed into the plant, thus contributing to the plant's competitive and reproductive fitness. For most carnivorous plants, nutrients are transmitted via diffusion through trap fluids. In some cases (i.e., Roridula), nutrients are first passed through the digestive tracts of mutualistic organisms and then deposited, as fecal matter, onto the leaves, whereupon they enter the plant through cuticular gaps.

The nutrients pass into plants by three mechanisms, depending upon the plant.

1. Some plants have specialized cells or cellular structures to allow for the absorption of nutrients. Examples include the stalked or sessile glands of Drosera or Pinguicula, or the quadrifid glands inside the bladders of Utricularia.
2. Nutrients may enter the tissues directly. The interior pitcher walls of Sarracenia lack the waxy protective layer called a cuticle. This allows the nutrients from the pitcher fluids to enter the plant.
3. Nutrients may enter the tissues through specialized gaps in the cuticle. In Roridula, breaks in the cuticle allow the nutrients from hemipteran fecal matter to enter the plants. Cuticular gaps are a big liability for plants because they expose the plant to dehydration or invasion by pests and disease, so a plant will not have such gaps unless they confer a real benefit to it.

Did you notice that, in my definition, I note that the nutrients must confer a benefit to the plant? This is important because it is the evolutionary drive behind selecting for carnivory. Plants will not evolve to be carnivorous if there is plenty of food present for it in the soil! For this reason, I don't think we will ever discover a carnivorous plant that occurs in rich, fertile soils.

What do you mean by "digestive mechanisms?"

• 
  Drosera schizandra
  glands
• Metriocnemus
  in Darlingtonia
• Cyrtopeltis
  on Ibicella
• Setocoris
  on Stylidium

Now we move to the second part of the three-part definition of a carnivorous plant:

A mechanism is present by which prey are degraded into a form that can be assimilated by the plant. The digestive mechanism may be enzymes produced by the plant, decomposition by bacterial activity, or other organisms in a mutualist relationship with the plant (i.e., arthropods as in the cases of Darlingtonia andRoridula).

All this means is that once the prey is captured, the prey must be digested into raw nutrients that the plant can absorb into its tissues. If you think of the trapping attribute as the plant's mouth, the digestion attribute is rather like the functions of a stomach. There are three ways that digestion can be performed:

1. The plant may produce its own digestive enzymes.
2. The plant may have internal parts that are populated with bacteria, mites, larval insects, etc. This is universal for all pitcher plants, even those that produce their own enzymes. Analogous to bacteria in the human gut, these organisms digest the prey for the plant.
3. The plant may have external surfaces upon which live organisms such as predatory/scavenging hemipteran bugs that digest the prey, then produce excrement that can be absorbed by the plant.

You should be a little careful when looking at plants with predatory bugs crawling around on their surface. Every now and then a carnivorous plant enthusiast will report on some possible "new carnivorous plant," and will cite as evidence the fact that they saw a hemipteran crawling on it. Beware! Hemipterans crawl around on a lot of surfaces and sticky plants--that doesn't make the plant carnivorous. It is crucial that the plant has clear adaptations by which it can absorb the nutrients from the hemipteran. If the excrement from the bug just rolls off and goes into the soil to be lost, that ain't carnivory!

What do you mean by "adaptations to capture prey?"

• 
  Drosera roseana
• Utricularia macrorhiza
• Dionaea muscipula
• Cephalotus

This is the first requirement of the three-part definition of a carnivorous plant. In its full detail, the requirement is (in somewhat technical language):

The plant must have clear adaptations to capture prey. Such adaptations may include specialized structures like trapping leaves, and/or enhancements to improve the luring and capture of prey, such as extrafloral nectaries, attractive UV or pigmentation patterns, odors, hairs that guide prey, etc.

There are two parts to this. First, the plant must have a trapping mechanism. There are five different trap types that carnivorous plants have.

• A sticky Salvia
  Is it carnivorous?

1. Pitfall traps--such as pitcher plants like Cephalotus;
2. Sticky traps--such as the sundew genus Drosera;
3. Lobster pot traps--such as the marvelous Genlisea;
4. Suction traps--the only genus that does this is Utricularia;
5. Snap traps--for example, the famous snapping leaves of Dionaea.

The second part of this attribute is that the simple trap type mentioned above might have modifications that improve its efficiency. I'll mention some as I describe the trap types later in the FAQ, but to whet your appetite I'll mention examples:

1. Plants might produce nectar as a lure;
2. Plants might produce an attractive smell;
3. The trap may have visual appeal--this may only be visible in UV;
4. The surface of the trap might be particularly slippery or waxy;
5. Hairs may be present that point prey to the point of no return;
6. Special trap windows may let light in, but not allow escape--this can disorient prey;
7. Trap fluids may be particularly sticky or viscous.

The importance of this attribute is that it is the basic method by which prey are captured so the plant can get on with the next stage---digestion!

Plant of the day - Nepenthes Truncata

Nepenthes truncata (pronounced /nɨˈpɛnθiːz trʌŋˈkɑːtə/, from Latin: truncatus = terminating abruptly) is a carnivorous pitcher plant species endemic to the island of Mindanao in the Philippines. The species grows at an elevation of 0–1500 m above sea level.^[1] Nepenthes truncata is characterised by its heart-shaped (truncate) leaves and very large pitchers, which can reach up to 40 cm in height.