Tropical Pitcher Plants and How to Care for Them
Tropical pitcher plants, or Nepenthes, are what most people think of when they think of carnivorous plants (CPs), second to Venus flytraps (Dionaea muscipula). Nepenthes do not go dormant and are easy to tell apart from the American pitcher plants (Sarracenia) by their growth pattern. Sarracenia have their entire leaves modified into their pitfall traps, which grow straight out of the ground. Nepenthes grow as vines and their pitfall trap is a modified midrib growing as an extension from a "traditional" leaf.
Nepenthes and differ with most CPs on their care. Venus flytraps, Sarracenia and Sundew (Drosera) are all bog plants, so they're all very similar to one another when it comes to conditions needed in order to thrive. Nepenthes is a widespread genus native to tropical and humid areas of Asia, Australia, and Madagascar where they grow under the tree canopy, which has very different conditions to a bog. Let's get into those differences!
Nepenthes grow under the tree canopy, sometimes even up the trunk of the trees. This means in the wild they have dappled light. Bright, indirect light is the best for these plants. Direct light or too strong of grow lights will cause sunburn. Once a leaf is burned, it will not heal. That spot will remain for the life of the leaf. Grow lights are fine to use in spaces that are lacking light, but be sure they are about 12-15 inches away from the plant to reduce the risk of burning. Some grow lights give off heat. If you notice your lights are radiating a lot of heat, raise them to ensure the plants don't burn.
Watering is where most people go wrong with any carnivorous plant. CPs have very sensitive roots and they cannot tolerate additional nutrients and minerals that are in tap and well water. The only safe water to use on CPs include rain, distilled, reverse osmosis, and dehumidifier water.
As far as how often to water your new Nepenthes, they prefer moist, but not wet conditions. When you water, allow the pot to drain so they do not sit in standing water too often. Unlike Sarracenia, which need to be sitting in water at all times, tropical pitcher plants will do best if allowed to dry slightly. Never allow them to dry out completely. Think of the moisture level of a damp sponge.
If grown outside, these plants will not need to be fed. They will lure and trap their own insects! That being said, popping the odd stinkbug or other annoying insect in a pitcher every once in a while will still benefit them. Be sure to not stuff the pitchers full of insects, as that will cause rot. An insect or two per pitcher is perfect! The insect is the correct size for the pitcher if it can fit inside without force.
When grown inside, insects are a lot harder to come by. Fertilizing is a tough game when it comes to any form of CP. Nepenthes are perhaps the easiest to fertilize. One pellet of Osmocote Vegetable fertilizer per pitcher is all you need. Do not fertilize more. Foliar fertilization is also an option but it is not easy and I do not recommend this for beginners.
Perhaps one of the most important aspects of growing Nepenthes is the humidity. These are jungle plants where fog is common. Growing them in a cloche, terrarium, or greenhouse cabinet where the humidity is much higher than that of your typical house will do wonders! If the plants stop making pitchers, they do not have adequate humidity. Placing them next to a humidifier is also a great way to achieve the levels they prefer.
When you receive your new plant, check the pitchers. During transit, the fluid will often spill out. Fill them about a third of the way with water. Once the plant adapts to your environment, it will produce its own fluid and you will no longer have to fill the pitchers. Don't be discouraged if this does not happen for a few months! Something else to keep in mind is that bottom leaves yellowing is perfectly normal. As long as the growth point is healthy and green, so is your plant! Just like you can't keep every hair on your head, your plants can't keep every leaf they make.
If pitchers start browning from the top, this is normal. Wait until the entire pitcher is brown before you remove it, as it can still be absorbing nutrients on the healthy portions of the pitchers.
As always, if you have any questions at all, send me an email with a picture of your plant and how you have been taking care of it and I will be able to help you!