Growing Carnivorous Plants
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If you are looking for a plant that brings a combination of excitement and beauty, look no further than the large and diverse group of carnivorous plants. With over 700 species found on all continents except Antarctica, it’s easy to find one that will grow well for you. When I visited Iceland a few years ago, I was surprised to see so many Pinguicula vulgaris, a vibrant blue flower, whose sticky leaves act like flypaper, peppered around many volcanic roads.
Currently, I am in Florida and have had a small carnivorous plant nursery for the past four years. I have shipped many plants across the U.S. I usually have about 1,000 plants in stock which comprise the infamous Venus flytrap, but also includes plants commonly known as bladderworts, butterworts, sundews, and three types of pitcher plants. While some people in Minnesota for example, order tropical pitcher plants, Nepenthes, which need to be grown indoors, others choose temperate species which enjoy the changing of the seasons and a dormancy period.
When I am at a plant show, carnivorous plant (CP) enthusiasts are very excited to see a carnivorous-plant-only vendor. People not familiar with carnivorous plants, often loudly pass the tent, saying things like “I can’t keep those things alive.” While the truth is that they do require different growing conditions than many other plants, once you know the three secrets, you’ll not only be growing them but propagating them and sharing them with friends.
“I have been captivated by carnivorous plants for 40 years now, growing up in the bush where many of these species thrived,” Richard Nunn the President of the International Carnivorous Plant Society tells me. “There’s something prehistoric and macabre about carnivorous plants. They have adapted to turn the tables on the insects that often make plants their meal.”
Nunn adds that “Despite the exotic nature of these plants, many varieties can be grown at home if some simple steps are taken. The International Carnivorous Plant Society website has a lot of information to help beginners grow these plants.”
Three secrets of growing carnivorous plants
Feeding/Fertilizers – One of the first questions I am often asked is, “What do I feed it?” If plants are kept outside, they will lure, capture, and digest prey on their own, like they have been doing for millions of years. If plants are kept indoors, you can supplementarily add a spider, fly, or other pests to the traps. Arthropods are the preferred diet for most of the plants that people keep. Although some CPs are known to digest protozoa, mosquito larvae, shrew and bat urine, detritus (does that make them a cannibal?), and the occasional small mammal.
Fertilizers are generally not recommended. They grow the healthiest when they have a meal. Some plants do well with diluted foliar fertilizer. I have had success with using the seaweed-based fertilizer MaxSea diluted to ¼ strength for my Nepenthes. The rest of the plants fend for themselves in my backyard. If you really want to get technical check out the International Carnivorous Plant Society’s growing guide section on their website. https://www.carnivorousplants.org/grow/guides
Water – Carnivorous plants are very particular in their water requirements. Many commonly cared for CPs including Venus flytraps, Sarracenia, Pinguicula and terrestrial Utricularia like to be sitting in a little bit of water most of the year. This is counterintuitive to many other plants – especially the now trendy houseplants. Many CPs are native to areas that have saturated soil for most – if not all – of the year. You’ll want to replicate these conditions if you are going to grow CPs successfully. This can be easily accomplished by placing your potted plant in a recycled deli container or a shallow saucer. The tropical pitcher plants, Nepenthes, grow in slightly drier areas and do best not sitting in water. Keep their potting medium moist.
Another aspect of water is water quality. Carnivorous plants do not tolerate salts, minerals, or other chemicals. Rainwater, distilled water, or reverse osmosis water is necessary. Typically hose water, tap water and well water have too many minerals which will build up in your CP soil and are detrimental. Depending on where you live, you may be lucky enough to use your tap water. Check the parts per million (ppm) with a water quality pen ($10-$15) to see if your water falls within the preferred range of 50 ppm or less. My tap water is in the 350 ppm range. Yikes!
Soil – CPs have evolved to obtain their nutrients from the prey that they eat. They grow well in airy, nutrient-poor soils. Most CPs that are native to North America do well in half perlite and half peat mix. A large bale of peat can be purchased for around $15 at most gardening centers. Nepenthes do well in long fiber sphagnum. You can also add in perlite for Nepenthes, but I have not found it necessary.
Venus flytraps are the most famous, but a little tricky to grow. They do best in tall pots that sit in 1/8 inch of water during the spring and summer. Grow them in full sun. The more sun, the more vibrant they become. One trick is keeping the soil damp, as they sit in the full sun. This is where the recycled deli container comes into play. You are trying to replicate a fen (type of wetland) remember? Healthy plants can handle their traps being set off by the occasional backyard tourist. Although is it best to place a meal in their trap, if you want to see them work. Traps will blacken and die after they open and close a few times. So you don’t want to tire the plant out. Around Thanksgiving to Valentine’s Day, they will go dormant. Leaves will die back and you may be left with a rhizome in a pot. This is normal. As a native to the Carolinas, they are perennials who are equipped to handle the seasons.
N. American pitcher plants have similar growing conditions to the Venus flytrap. Some are short and squat like Sarracenia purpurea and others like S. flava and S. leucophylla can reach almost 4 feet high! These do a great job catching wasps and moths.
“Sarracenia make great patio plants if your water is low in dissolved salts and you have a location with lots of sun,” John Brittnacher, Vice President of the International Carnivorous Plant Society says. He adds, “For Sarracenia, the plants should be bog pots with drain holes in the sides so water is retained in the pot. During warm weather, they must be watered every day.”
Sundews – especially the cape sundew (Drosera capensis), are a great beginner CP. These grow year-round, do not require a dormancy period, and unlike the Venus flytrap, they can be grown indoors on a sunny windowsill. The sticky elongated leaves are really good at trapping fungus gnats and fruit flies.
Butterworts have leaves that are covered in mucilage, which are great at catching fungus gnats and fruit flies. Brittnacher says, “If you can grow African violets, you can grow Mexican Pinguicula. Same light requirements. Same soil. A little more water.”
Nepenthes are one of the most trendy CPs. There are two factions: the highland species and the lowlands. Highland Nepenthes grow in cloud forests on the top of mountains. They like cooler temperatures ranging from 70-80s during the day and 50-60s during the night. Many of these beautiful plants do well indoors on sunny windowsills. Lowlands, which are native to the foothills of tropical mountains, need high humidity and constant temperatures in the 80’s. These do great outside in Florida, in greenhouses or spacious heated terrariums.
“These amazing plants make an interesting and attractive addition to any home or ranch garden and have the added bonus of catching those annoying mosquitos and other bugs that test our patience during those summer months,” Nunn says. “Warning, growing carnivorous plants is very catchy and can become addictive!”
To learn more about the other genera and hundreds of species, check out the International Carnivorous Plant Society at www.carnivorousplants.org.
Originally published in Countryside November/December 2021 and regularly vetted for accuracy.