If you have a pitcher plant, you are familiar with its appearance: its glandular leaves looking like open mouths turned up to the sky, just waiting for insects to eat. They are quite temperature tolerant and can be partially cold hardy, but not below USDA zone 7. They need insects to eat, so they need special care to survive through the colder months.
How to take care of a pitcher plant in the winter: The key to caring for a pitcher plant is mimic its normal habitat. That means ensuring they have a period of dormancy whether they are indoors or outside.
Pitcher plants are bog plants and are often grown as part of a water garden or at the edge of a water feature. They are a carnivorous plant from the genus Sarracenia, which includes 15 different varieties. These are plants that trap/capture insects as part of their nutrient needs. You want your pitcher plant to make it through the winter, so let’s talk about how to make that happen.
Pitcher Plants and Your USDA Hardiness Zone
Pitcher plants are a carnivorous plant that grows in North America. There are fifteen different variations. The plant likes to grow in moist conditions and is often found near water. They are considered a bog plant. They like peat type soils. The poor soil that is low in nitrogen is the reason they capture and digest prey.
How you care for your pitcher plant will depend on what hardiness zone you live in. Most varieties need zone 6 or 7 to grow as extreme cold in the winter will kill them. But – here’s the key – they do need some chilly temperatures to ensure a period of dormancy.
- Plants that thrive in zone 6 will survive cold snaps.
- Plants in zone 7 may need some help during freezing weather but can usually stay outside.
- One variety is cold hardy to zone 5 and can survive outside all winter. However, other varieties grown in colder zones will have to be brought inside during winter months.
Caring for Pitcher Plants in the Winter
Plants in USDA zone 6 can accommodate short periods of freezing weather. The cold will help the pitcher plant enter dormancy. When the weather warms, that will signal the plant to end its dormancy. The colder period to begin dormancy is important for all varieties of pitcher plants.
- For plants growing outside: in extreme cold, the plants will need a thick layer of mulch to protect the roots.
- For those growing in water: they will need to be kept in full water trays with the ice kept breaking.
- For those plants that have to brought inside in the winter: they will need special care to ensure they enter and then come out of dormancy.
Pitcher plants that are brought inside need to be placed in a cool, covered location. An unheated garage or basement where the temperatures are below 60 degrees is ideal. The plant will need reduced water and no fertilization during this time period. The length of time will vary with variety, so it is important to know which variety and what their natural cycle of growth and dormancy is.
Pitcher Plants as Houseplants
Be warned: carnivorous plants can sometimes make very finicky houseplants. Growing pitcher plants in the house requires copying the typical growing cycle they would have outside like when they are brought indoors for the winter.
- The plants need warm, moist air with at least 30% humidity at all times during their growing periods.
- They need acidic soil, similar to peat.
- The growth-dormancy cycle will need to be created:
- Move the plant to an area of cooler temperatures and lower light
- Care for it in its new environment for three to four months
- Reduce water and fertilization during this time.
- After a dormancy period, the plant can gradually have increased light, heat, and water.
- Fertilization may be needed to encourage growth.
- Pick the right pot:
- Plastic or glazed ceramic pots will help keep the soil moist and are best.
- Unglazed terracotta pots will dry out the soil, leach salts into the soil.
- Plastic pots with drainage holes can also be used, especially with using the tray method to increase humidly.
Why Fertilization is Important
Turning leaves into specialized traps can use lots of energy. The traps cannot photosynthesize efficiently. So, the plant gets less energy from the sun and has to spend more energy than other plants when they spring their traps.
The traps will only close four or five times before they curl up and die. The plant then has to expend more energy to create another one. So, it needs to have adequate intake to keep going.
Maintaining an Indoor Pitcher Plant’s Diet
Pitcher plants cannot survive on photosynthesis alone, even with fertilization. So, they will have to have a source of bugs. This may mean catching or buying bugs and feeding them to the plant.
All of this means that pitcher plants can be difficult to maintain as houseplants.
Dormancy is the period of time during which the plant stops growing and developing. For plants in colder regions, they often “die back” and can appear as if they are dead. The purpose of dormancy is to conserve energy. Many plants enter it due to environmental conditions, such as cold temperatures, that would limit the plant’s ability to function and create their own food.
- Winter dormancy is when a plant’s dormant state is triggered by reduced light or cooler temperatures in what is called predictive means. This allows the plant to completely become dormant before the onset of adverse conditions, even colder temperatures.
- Consequential dormancy is when plants do not become dormant until after adverse conditions exist.
- Predictive dormancy is when a plant enters dormancy before adverse conditions. This is what most carnivorous plants, including pitcher plants experience.
This makes it important to know the normal growing conditions of the specific pitcher plant you are growing. The dormancy will need to be triggered and ended at the same time as if the plant was living outside. This is true whether the plant is always inside or just brought inside for the winter.
Pitcher Plant Problems
Most pitcher plant diseases are caused by either cultivation or environmental issues. However, they do have some diseases and pest problems that need to be monitored.
- Freezing temperatures before the plant is fully dormant can kill the root system. If it is suspected that the roots were damaged, they will need dug up and inspected. The rhizomes should be firm and white. Any that are mushy or discolored will need to be thrown away and new ones planted.
- Pitcher plants need boggy soil. If planted in clay soil, the soil can retain too much water. Proper drainage and the right soil will help keep the plant growing well. Pitcher plants that are grown inside need the proper potting soil and drainage.
- Pitcher plants are sensitive to chemical drift from pesticides or herbicides. It is important when spraying to make sure they are protected, and the wind is not blowing towards them.
Except in the case of those plants grown indoors, pitcher plants typically should not be fertilized. They harvest their own nutrients through trapping and digesting prey. Pitcher plants have adapted to low nutrients soils. But your plant can still need your help in times of poor health or disease.
Plants that are grown indoors may be unhealthy and have a yellowish coloring due to too few insects. These plants may require fertilization. It is important to pour the half diluted liquid plant food straight into the pitcher with water in it.
Pouring fertilizers on the soil can lead to spores to grow in soil. Fertilization can cause these spores to multiply rapidly. The result can be common fungal diseases. The diseases can then enter the pitcher plant through the roots and destroy the plant’s foliage or vascular system.
It would be easy to believe that pitcher plants have nothing to fear from insects as they would just eat them. However, some smaller insects exist that are too small and too many for the plant to consume and protect itself. These insects can be very persistent and create severe damage if left unchecked.
- Spider mites attack in hot, dry weather. They can be prevented or minimized by keeping the plant moist.
- Thrips are teeny insects that cause deformed leaves. They are almost impossible to see. One way to check for them is by holding a white paper under the leaves and shake. Tiny black spots on the paper signify they are present.
- Aphids, leafhoppers, and mealybugs will also attack pitcher plants.
Neem oil and water rinses can be effective in controlling pests. Killing bugs near a carnivorous plant is tricky. Care must be taken to protect the plant by killing the “bad” insects, while also ensuring that the “good” insects (its prey) will not all be killed also. Always follow directions when using any pesticide.
Pitcher plants can tolerate dry air, but they will often stop producing pitchers. For pitcher productions, the humidity needs to be at least 50%. Misting the plant regularly can help with increased humidity.
To up the humidity, the plant can be placed on a tray of wet pebbles or gravel. The pebbles can be kept constantly wet. The bottom of the pot needs to be above the waterline of the tray to keep the root from becoming too wet.
Placing the plant in a grouping of other plants can also increase humidity in that area. Terrariums can be used in houses with really dry air. It is important to avoid air-conditioned rooms as they will have the lowest humidity.
Watering using filtered, distilled, or rainwater. Tap water should be avoided when possible. If using tap water, distilled water will need to be used for flushing hard water minerals.
Because carnivorous plants have adapted to live in poor nutrient soil, the minerals in tap water can overwhelm their roots and system. This can lead to plant death, similar to over-fertilization.
Carnivorous plants, in general, can be difficult to grow inside. They can take extra care. The three easiest to grow carnivorous plants are:
- Drosera capensis, the Cape sundew: one of the prettiest and most entertaining sundews, this species is also one of the most adaptable. A great flycatcher and a perfect plant for new growers.
- Dionaea muscipula, the Venus flytrap: Not quite as easy to care for as the Cape sundew, but just as awe-inspiring and rewarding to grow
- Sarracenia purpurea, the Purple pitcher plant: This species is the most tolerant of all North American pitcher plants. It’s also smaller than the erect species, and its squat pitchers make it suitable for windowsill growing.
Springing a Pitcher Plant’s Trap
It is important to not “spring the traps” of a carnivorous plant just for fun as this can damage the plant and shorten its life. Each trap can only be used by the plant a few times before it falls off and has to grow a new one. This will deplete the plant’s energy without supplying any.
Make sure everyone in the household knows that it’s not a good idea to play with the plant’s traps. Doing so will rob the plant of energy they can replace through photosynthesis, while not allowing them to gain any energy though digesting prey.
Following the care instructions for a carnivorous plant can seem tedious, but pitcher plants will grow the best if some thought is given to recreating their normal growing conditions inside.
Does a Pitcher Plant Use Photosynthesis?
Photosynthesis is the chemical process most plants use to create their own food. The plant takes in nutrients and water through its roots and carbon dioxide in the air.
The chlorophyll in the leaves uses sunlight to fuel this chemical process that turns the water and carbon dioxide into sugar and oxygen. The sugar is then used by the plant as food, and the oxygen is released back into the air.
The photosynthesis process is why most plants do not have to consume other living organisms to live. They have all their nutritional needs met through creating it and through the soil.
However, not all plants are capable of supplying their own food this way. Some plants that grow in soil poor in added nutrients have adapted to eating insects to meet those needs.
Yes, pitcher plants to photosynthesize. But they can’t get the nitrogen they need this way, of course. And they can’t take it from the soil. So, they need to supplement their own diet to survive, by catching bugs.
Carnivorous plants have adapted to less than ideal growing conditions by being able to trap and digest prey to meet their dietary needs that the soil is not providing, often nitrogen. They have developed a variety of different ways to trap insects.
There are over 580 species of plants that attract, trap, and kill prey and another 300 protocarnivorous (borderline) plants that show some of the characteristics.
Carnivorous plants have developed five basic trapping styles. Traps can also be passive or active, depending on if the plant has adapted ways to make their parts move to more ably trap and digest the prey. Some plants have tendrils that they can use to attract prey. Others can move to trap the prey making it less likely they will escape.
Pitcher plants is a generic name given to many different pitfall trap plants. Many of these plants do catch water as well as insects in their pitcher-like traps.
However, each plant does have a specific scientific name and common name, so as not to confuse them with the common pitcher plant (genus Sarracenia, that grows in the United States. They are also the easiest to cultivate and grow.
- These plants are characterized by an internal chamber filled with digestive enzymes that the prey is induced into.
- Once they are in the trap, the insects are not able to climb back out.
- A pitfall trap is a passive trap that attracts prey through nectar or bright coloring within the pitfall.
- The lining of most pitcher plants has a loose coating which is too slippery for insects, causing them to fall and be trapped.
Pitcher plants are one of the simplest pitfall trap plants. Some pitcher plants’ trap is so simple it only consists of a rolled leaf with sealed edges that captures the prey. Other plants have more elaborate inner chambers. Others have their pitfalls at the end of tendrils. Some plants in the tropics have been known to get big enough they have caught small mammals and reptiles.
Most pitfall traps are only passive, relying on the prey to find and get trapped in the pitfall.
Flypaper traps use a sticky coating that is glue-like to capture their prey. These plants can be passive, in that they just wait for the prey to land and get stuck. The coating on the leaves is released when the plant senses prey. Once the prey lands, the glue-like substance means they cannot escape. Digestive enzymes can be secreted like glue.
Other flypaper trap plants are more active as with the Sundew plants, that can make tendrils bend and move, making it easier to trap its prey. Some flypaper trap plants are able to roll their leaves, quickly trapping the prey even before it is fully stuck. All of these adaptions make it easier and faster for them to trap prey.
The most commonly known snap trap plant is the Venus flytrap. These plants have rapid leaf movement that catches the prey. Only two active snap traps are known to exist. The Venus Flytrap and the Waterwheel Plant.
The Venus Flytrap catches many different arthropods, including spiders. The Waterwheel plant is more aquatic and catches small invertebrates in the water.
These plants both have trigger hairs inside trap lobes that are sensitive to touch. When prey touches or bends a trigger hair, a process begins that results in changing the shape of the cells allowing the lobes to snap shut on its prey.
The exact mechanism that leads to the rapid growth and leaf movement is still debated. The whole process can take less than one second.
The Venus flytrap had adapted to keep rainfall from triggering the snapping mechanism. The leaves have a simple memory. The plant must have two touch stimuli without a short period of time to shut. Once the leaves are shut, the prey’s struggles cause them to tighten more. The closed leaves become a stomach with digestion taking 1-2 weeks. Leaves can repeat this process 3-4 times before they stop.
Bladderworts are the only known plants that use bladder traps. These plants have bladders that excrete ions. Water follows causing a vacuum inside the plant’s bladder. Aquatic species have trigger hairs similar to those in a snap trap that causes a hinged door to deform and suck in the aquatic invertebrates.
Terrestrial species grow in waterlogged soil with no roots. They have anchoring stems that are similar to roots. They have a slightly different triggering mechanisms. However, their trap remains a bladder that pulls the prey in.
Much like a real lobster-pot, these plants have a chamber that is easy to open, but hard to exit. The exit may be difficult to find or have an inward-pointing barrier. The trap is often lined with hair that keeps the prey moving towards the center so that they don’t escape. This also leads them to the digestive enzymes. Prey movement may also be encouraged by water movement similar to the bladder trap.
Some plants have a combination of traps to catch their prey. This is probably because they have started with one type and over time, developed other ways. The most well-known combination trap combines the flypaper and snap trap. This is found in a specific variety of sundew plants. It is considered a catapult-flypaper trap.
Borderline Carnivorous Plants
Some plants are considered borderline carnivorous. To be considered carnivorous, a plant must have two characteristics. It must have an adaption that allows it to attract, capture, or kills its prey. It must also then benefit in some way from that prey. Plants that have only one of these characteristics is considered borderline or protocarnivorous plants.
Some plants may kill insects in defense but obtain no nutrients from them. Others obtain nutrients from dead insects and animals, but not trap and kill them. These plants do not have both characteristics. So, they are not true carnivorous plants.
Botanists disagree on how some plants should be classified. It is thought that over time, these plants will continue to develop into fully carnivorous plants.
Little Shop of Horrors and Other Myths
Little Shop of Horrors is based on the idea of a carnivorous plant that first eats blood and then finally full-sized humans. The story is based on legends and myths about carnivorous plants. Stories of man-eating plants came to live in the 1880s. Stories of explorers watching someone stumbled into a never before seen plant and being eaten alive were common.
The stories, like many legends, were second-hand. One of the most gruesome accounts came from a scientist named Karl Leche. Some accounts were made more believable because other real and strange plants were discussed in the same narrative. Decades later, these stories were exposed as false. Even once people knew the stories were false, the idea of a man-eating plant survived.
The Obsessed Botanist
The obsessed botanist is another subset of the man-eating plant stories. The fictional stories focus on a botanist that is obsessed with keeping a strange new plant alive. Many of these stories have similar themes and ideas. In almost all of these stories, the plant in question grows much larger and is much more mobile than any carnivorous plant alive today.
One of the first is from 19th century France and is a clear precursor to Little Shop of Horrors. A botanist tries to keep a Venus flytrap type plant alive in secret. His wife and friend sneak into his laboratory. The plant tries to eat the wife by pulling her into its “mouth” with tentacles. The friend saves her by chopping the tentacles. The botanist dies heartbroken by the loss of his plant.
It’s clear that carnivorous plants have long been a subject of interest to people and it’s no wonder why. Pitcher plants and other insect-eating vegetation are fascinating to live with.
Pitcher plants are a typical carnivorous plant that is fun to grow. However, to survive, these plants need to be provided with periods of dormancy since they are not hardy enough for extreme cold or long periods below freezing. They also require proper humidity and soil conditions, whether growing inside or out.
Plants in colder regions will need to be brought inside for the winter, but they will still need to be kept cool enough to have dormancy over the winter months. Pitcher plants do have their needs. However, if you are willing to take the time, they can be really fun to grow