Oudean's Willow Creek Nursery
Carnivorous Plants

 

"The Care and Feeding of Nepenthes, Tropical Pitcher Plants"ã2001
By Karen Oudean

     Nepenthes are tropical pitcher plants, found in areas of high humidity and frequent rains.  Most of the species are native to Southeast Asia.  A few of the estimated 80 species are found in other parts of the world in similar conditions.  Unlike the North American and the South American pitcher plants, the pitcher is not made up of the whole leaf.  The pitchers occur at the ends of the leaves on tendrils that help the plant climb the surrounding shrubs and trees.  Not all tendrils produce the jug shaped pitchers.  If a tendril produces a pitcher, its tip plumps up until a hollow, closed pitcher appears.  As the pitcher matures, the lid pops open.  The pitcher, already filled with digestive fluid, quickly reaches maturity, ready for business.  Glands, all over the plant and on the inside of the lid and lip roll of the pitcher, produce a sticky, intoxicating nectar that attracts bugs.  The tempting lip roll and the waxy surface just inside the pitcher, practically guarantee the insects a downhill slide to a watery grave.   The lower or ground pitchers on the plant have little wings running vertically down their fronts.  The upper pitchers, on the climbing stems, are more slender and without wings.  The pitchers are the reason Nepenthes are so popular.  The flowers are ornamentally insignificant to most people. 

     Nepenthes species are divided into two groups according to habitat.  Lowland species grow at elevations below 3000 feet above sea level, where the days are hot, the nights warm and the humidity high.  Highland species grow from 3000 feet to 10,000 feet above sea level.  The climate is cooler and rain or heavy mist is frequent.   

     Nepenthes gracilis, a lowland (warm) species, is a very good choice for beginners.  If the humidity in your home is at least 50%, it may produce pitchers, 6” – 8” away from the glass, in a southeast window. Make sure it is not next to or above a heat vent. The temperature should be a minimum of 60°F at night.   Daytime temps can range from 70°F to 95°F.  Daily misting with distilled water helps the general health and pitcher production of the plant.  If the plant does not produce pitchers in a few months, the humidity is probably too low.  Nepenthes gracilis will grow happily in a pot, in a warm steamy terrarium with an 18W fluorescent plant light in the hood.  Place 1” to 2” of aquarium or granite gravel over the bottom of the terrarium so you can maintain a water level about 1” to 2” deep to raise humidity. Place the pots on top of the gravel.  Landscape the tank with another inch of gravel around the pots.  Arrange live sphagnum moss, rocks and freshwater driftwood on top to hide the pots.  Keep the tank out of direct sun or you will cook your plant.  If the plant wants to outgrow the tank, give it a haircut with a sharp pair of scissors. New shoots will rise from the leaf joints and the base of the plant.  Most other species of Nepenthes prefer to be trimmed only in spring after a new shoot develops at the base of the plant.  Other good choices for warm terrariums are N. ampullaria (climbing stems may be pruned as with N. gracilis), N. bicalcurata (when it is young), and N. mirabilis.  Terrariums situated in rooms that are cool at night may work well for highland (cool) species such as N. madagascariensis and N. ventricosa.  Many highland species such as N. khasiana and N. sanguinea grow well and produce pitchers in bathrooms and kitchens with good light.

  1. Temperature Requirement:

      A.  Lowland Species:

      In terrariums, daytime temperatures should be a minimum of 650 F.  700F – 800F is better with night temperatures of 600F650F.  This is not hard to achieve if you are using a florescent plant light in your terrarium hood.  Our house gets cool at night even in the summer.  Leaving the plant light on 24 hours a day saves on home heating costs and has had no apparent ill effects on the plants.

      In warm greenhouses, in the summer, my plants have grown well with day temperatures over 1000F and night temps over 650F.  I keep the winter temps at 550 F at night and 600F in the daytime.  The plants frown at me.  10 degrees higher both night and day would be better.

B.    Highland Species:

           For terrariums, it takes a cool room and a cool (commercial) florescent light in the hood.  Night    

      Temperatures may be allowed to drop to 400F. Daytime readings should be between 600F and   

      700F.  I use the same temperature settings in the cool greenhouse.

  1. Light Requirement:

      I use 18W florescent lights in terrariums.  Lowland species like plant lights.  Highland species do fine with cool florescent tubes.  If the pitchers lack color, add another light by the side of the tank or place the tank close to a sunny window, just back from the area the sun actually shines on.

      I place the plants in areas of my greenhouse that only get direct light in the morning, or put them in the shade of other plants. You may need shade cloth.   

  1.  Water Requirement:

     Nepenthes are not bog plants in the sense that pitcher plants and Venus’ flytraps are.  They do, however, grow where rain is frequent.  They need well-drained soil that is constantly moist.  In the kitchen and greenhouses, I allow a ½” of standing water in the pot saucers; but let it evaporate between waterings.  I use distilled or rain water.  I keep the water in the terrariums just barely above the gravel the 21/2” – 51/2” pots rest on.  Watering is less frequent in the contained environment.  I water the pots from the top when the water level in the gravel drops.                                                                        

 4.  Humidity Requirement:

     The best pitchers are produced at over 60% humidity.  A friend of mine uses a cold steam vaporizer with great results.  Some plants will grow well at 50% humidity but not pitcher out.  Some like N. bicalcurata will get black edges on their leaves and may even die.  Terrariums and greenhouses provide the best answer for many people.  However, satisfactory results can be achieved with highland species in kitchen and bathroom windowsills where humidity collects.  I have had good results with lowland species in the house using a plastic shelf unit.  I attached under-the-cabinet light fixtures to the under side of the shelves, above the plants, placed it near a window and wrapped the whole thing with a clear plastic drop cloth.  I used clear packing tape to anchor the plastic and overlapped the front pieces to allow access while keeping the humidity in.    

Potting Instructions:

     If your plant was shipped to you bare-root, wrapped in moss, plant the roots with the moss after carefully loosening it.  Do not touch the roots with your fingers.  I use a soil mix of 4 parts peat moss, 1 part perlite, and 2 parts fine orchid bark.  The amounts do not have to be exact, as long as the resulting mixture drains well.  Mix the ingredients well and moisten them thoroughly.  A 4” – 6” pot with holes is best for young plants.  I prefer plastic pots; but glazed ceramic pots are fine.  Place a little sphagnum moss or orchid bark in the bottom of the pot to keep the soil in place.  Add enough soil mix to the pot so the bottom leaves of young, bare root plants will be just above the final soil level.  If you are transplanting your established plants, place enough soil mix in the pot to bring the plant to its former soil level in the new pot.  Tamp and water the soil mix.  Gently place the root ball in the pot.  Do not press on the roots.  Cover the roots with soil.  Lightly press the soil down.  Tap the bottom of pot, finish filling, and water the plant into the soil.  Give the pot another tap to grow on.

For more information:  There is an excellent TIME/LIFE videotape at most public libraries entitled "Death Trap".  Timber Press carries the book "Carnivorous Plants of the World” by Pietropaolo and Pietropaolo.  “The Savage Garden” is a great new book by Peter D’Amato.