Venus flytrap – Dionaea muscipula
With its menacing teeth and snapping jaws, it’s no surprise that the Venus flytrap has become the poster-child of carnivorous plants. This famous plant’s animalistic appearance almost makes it feel as though it is a thinking, calculating predator. In fact, it even exhibits some fascinating “behaviors” that make it seem like a living beast. For example, when something touches the inside of the plant’s jaws, it can tell whether the object is a bug or merely a piece of debris. Like other predators, the flytrap is selective about its prey; its teeth are designed to allow tiny insects to escape so that it can save its energy for a heartier bug that will satisfy its appetite.
Flytraps are relatively easy to grow even if you’re a beginner, so use our tips below to cultivate the best Venus flytraps you possibly can!
Biology of a Venus flytrap
The trap of a Venus flytrap is a highly-evolved leaf structure and one of the most fascinating mechanisms in the plant kingdom. It leverages a tripwire system, internal timer, and electrical impulses to force rapid movement. Traps are 1/2 inch to 3 inches long based on the flytrap variety. You’ll find them at the end of a leaf base called the petiole. Sometimes these petioles hug the ground – great at catching crawling insects, other times, they suspend traps in the air – great at catching flying insects.
The trap is a complex mechanism and the lifecycle can be broken down into 4 major steps:
After a newly formed trap opens, it immediately begins luring insects using sweet nectar secreted within the trap and, in some varieties, bright red coloration. 6-8 small trigger hairs are dispersed within the “mouth,” which function as insect trip-wires.
If one or more of the hairs are touched twice within a 20 second time frame, an electrical impulse shoots along the outer cellular wall of the trap, rapidly expanding these cells, lengthening the lobes, and forcing the trap to snap shut in as fast as one-tenth of a second. With the teeth of the trap now intermeshed, the insect is imprisoned in a digestive cage.
If the insect is small, it will escape between the intermeshed teeth and the flytrap won’t waste energy digesting a tiny insect that won’t provide ample nutrients. Similarly, if a stray leaf were to trigger the trap, the lack of continued movement would allow it to reset without wasting more energy (there are no vegetarian Venus flytraps). However, if the insect is too large to escape, it will continue to struggle inside of the closed trap, further stimulating the trigger hairs. The plant’s response is to seal the trap, secret digestive enzymes via glands on the inner surface of the trap, and digest soft tissues of the insect over the course of four to ten days.
Once the insect soup is absorbed by the trap, it will reopen to reveal the dried, shriveled exoskeleton of the insect. This husk may attract additional scavenging insects which then become a second meal for the plant, and the cycle continues. A trap can catch one to three meals before it will turn black and die. This is normal, and the plant will use the energy gained from that trap’s meals to grow new ones.
Sub-soil biology and requirements
Perennials, flytraps die back during the winter months, enter dormancy, and rely on the few thick, black roots branching from the rhizome to survive cold climate. They return from the rhizome during spring, starting the season’s growth with a rosette of ground-hugging leaves and smaller traps.
Dionaea will clump, splitting growth points and sending up offshoots. You can separate individual plants as long as each one has a few roots to support the new plant. Use the water tray method to keep soil constantly moist (but not waterlogged) during growing months, and reduce watering during dormancy.
They take approximately four to five years to reach maturity, at which point they’ll be their maximum size, and send up flowering stalks in the spring.
Flytrap flowers will shoot up on stem about one foot tall in early spring as the plant awakens from dormancy. Each flowers immediately releasing pollen from the anthers upon opening, and stays open for a few days. The stigma only becomes receptive after two or three days when it starts to look fuzzy. At this point, you can gently collect the yellow pollen using a toothpick and apply it to the stigma. If multiple flowers are open at the same time and stigmas are receptive, rubbing them together is an easy pollination trick. Pedals will close and wither after pollination occurs.
After six weeks, you’ll notice clusters of small, black shiny seeds that can be collected and refrigerated for future sowing, or sowed immediately. Check out more info, below, for tips on germinating your Venus flytrap seed.
Where to find Venus flytraps in the wild
Venus flytraps are native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. Unfortunately, due to their fascinating nature, they have been illegally poached from native habitats where their conservation status is now “vulnerable.” As a conservation effort, Dionaea muscipula has been naturalized in the Florida panhandle, New Jersey and California. Do your part to preserve these wonderful plants in the wild by purchasing from reputable retailers who cultivate in greenhouses.
Cultivation, growing techniques & propagation
Use distilled or reverse osmosis water. This can be inexpensively purchased in most grocery stores, or I recommend that you invest in a reverse osmosis (RO) filtration system that hooks up to a sink (bonus – this also provides great drinking water for humans and pets). Keep the plant in a water tray and fill this tray to maintain damp-to-wet soil year round. Avoid overhead watering as you may accidentally trigger traps, and will compact the soil around the root system. Maintain a lower water table by using a shallow water tray (1.5″-3″) as flytraps don’t appreciate persistent waterlogged conditions.
Flytraps enjoy full-to-part sun. Brighter conditions will promote red coloration in the traps, genotype-permitting. I’ve grow them with great success in direct, sunny Southern California light.
Probably the best part about owning a Venus flytrap! They’ll frequently catch their own food if grown outdoors. For indoor plants, and as a great party trick for friends, they’ll happily eat any bug that reasonably fits in a trap – from meal worms, to flies, and even spiders. If feeding live insects isn’t your thing, you can use moistened, dried insects that can be found here or at pet food stores (lizard food). Do note that you will have to manually trigger the trap if feeding with deceased or immobile prey.
Avoid fertilizing. Remember, these plants grow naturally in nutrient poor soils – a major reason why they evolved traps to catch insects as their source of nutrients. Fertilizing can burn flytrap roots and easily kill the plant. Some advanced growers use an extremely diluted fertilizer to foliar-feed plants (applying it only to the leaves of the plant), but this is risky for a beginner and not recommended.
Transplant in later winter, during but towards the end of dormancy. A transplanting into fresh soil every one or two years will promote healthy growth.
Flytraps will frequently produce offshoots and develop into a clumping plant. This sea of flytraps looks great, but you’ll promote even more new growth by dividing these clumps and repotting them in late winter towards the tail-end of their dormancy period. Do make sure that each crown of leaves has its own root system before dividing.
Like a handful of carnivorous plants, Venus flytraps can be grown larger, faster from cuttings. Using this method, expect mature plants in two years:
Healthy leaves can be peeled off the main rhizome in late spring or early summer and used to grow new flytraps. Simply use a downward tug to remove a leaf that includes a smallish portion of the white rhizome. Lay this leaf flat on the usual soil mix, or on sphagnum moss and cover the white base with a small amount of soil. Maintain bright light, high humidity (using a humidity dome or plastic bag), and moist soil. A few weeks later, plantlets will sprout from the base and after a few months, you’ll have rooted, growing flytraps.
Seed can be sown within the same season it is collected, or can be refrigerated in a small jewelers bag or envelope for future germination. To sow the seed, mix a flytrap’s preferred soil of sand and peat and pre-moisten with purified water. Sparsely spread the seed across this medium, and keep in a bright, humid place. It’s easiest to use a simple seed tray with a humidity dome. Germination will take a few weeks, and seedlings can be transplanted into a more permanent home after a year.
Flytraps take well to tissue culture propagation using leaf cuttings, seed, or flower buds.
Black spot fungus can appear on plants if they’re consistently humid and wet. Common fungicides like Physan will help, but avoid those that are copper-based as they can kill carnivorous plants.
Darn aphids… you’ll know they’re attacking your plants when new leaves appear gnarled and malformed. Diazinon, Orthene, and Malathion are effective and flytrap-safe pesticides to rid your plants of the little devils.
In hot climates, you can also encounter spider mites – use Orthene.
It’s enough to make you think that we need carnivorous plants to protect our carnivorous plants.
They are warm-temperate plants enjoying warm-to-hot summers and cold winters. Mostly tolerant of light frost and brief freezes.
Flytraps will thrive in temperate, warm-temperate, and Mediterranean-like climates.
They do well in cold houses, cool houses, and warm houses, and in cold frames in warm-temperate climates.
Can be seasonally grown in a greenhouse-style terrarium tank, but are best removed in winter during their dormancy period.
Will thrive in sunny windowsills. Added bonus – flytraps eat those pesky house flies that hover near windows when trapped indoors. Keep the plants cooler during winter dormancy.
Great candidates for bog gardens, flytraps do well in temperate, warm-temperate, and Mediterranean-like climates. They’ll grow great alongside many sundews (Drosera) and North American pitcher plants (Sarracenia). Mulch in colder areas to prevent long freezes.