Venus flytraps (Dionaea muscipula) are carnivorous species native to the watery peat bogs of North and South Carolina.
They’re best known for their striking colors – red, yellow, green, and blood orange – and their unique method of catching prey.
When an insect or a spider disturbs the hairs on the upper surface of their leaves, the trap will snap shut and the plant will slowly digest its prey.
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Unfortunately, wild populations are considered endangered due to habitat loss and poaching. However, they are available commercially in a way that does not impact wild populations.
In our guide to growing Venus flytraps, we cover how to cultivate these unique specimens in your home.
It can be very disappointing to find the striking colors of your carnivorous beauty fading to an inky black.
Can anything be done to save your plant or prevent it from happening again? That’s what we’ll cover in this guide. Here’s the lineup:
Sometimes, a Venus flytrap turning black just signals that it’s entering dormancy.
When the days grow colder and shorter, this triggers the plant to die back, conserving energy in the rhizome. The foliage will turn black before it eventually wilts.
This is completely normal and the colors will return when the long days and warmer temperatures return.
Venus flytraps require about ten weeks of dormancy to have strong growth next season.
If you have your plant inside, place it in an area with low light and cool temperatures for three months.
If you do this, be aware that the lowest temperature your flytraps can be subjected to is 45℉ (7.2℃). You can provide this by placing the plant on a porch or in a basement.
After three months, move your plants back into their warm, brightly lit area or back under a grow light and they will start sprouting again.
But why is turning black a common phenomenon when the temperatures are warm and the days are long?
Traps can turn black for a variety of reasons, including inadequate light or the wrong type of water. It could also be an issue with the potting media they are growing in or a response to damage from pests.
If it’s not the right time for the plant to be going dormant, then let’s take a look at the top five reasons why your Venus flytrap may turn black and what to do about them.
1. Not Enough Light
Since Venus flytraps are used to direct light exposure, they need at least six hours – preferably 12 hours – of sunlight per day.
Without it, they will start to turn black and potentially die through lack of photosynthesis. Thankfully, this is an easy problem to fix.
If you are lucky enough to have an area in your home that receives six hours or more of bright light, then you are golden. Simply move the plants into an area with sufficient light and they should recover.
If your home is naturally quite dark, you may need to use a grow light to provide the sunlight your plants need.
When choosing a grow light, you will need to purchase one that is at least 40 watts, and keep it on for 12 to 16 hours per day to mimic natural light.
45 Watt LED Panel
I would recommend this 45 Watt LED grow light panel available from AeroGarden.
I love this model because the stand height is adjustable and it can be tilted over your Venus flytraps to provide direct light.
2. Pest Infestation
When grown outdoors, Venus flytraps have natural enemies such as birds, raccoons, and squirrels, who will happily dig them up or cause damage.
However, inside your home, the biggest problems for these carnivorous plants are aphids and spider mites. In the case of a large infestation, black spots may appear on the leaves, especially on young, new growth.
Aphids can be green, brown, or yellow in color and feed on the leaves by sucking the sap. To get rid of them, pick them off with tweezers or gently wash them away with water from a spray bottle.
Spider mites look like tiny dots scurrying across the foliage. To get rid of them, spray your plant with a miticide that will help kill the pests and help to prevent future infestations.
Once the pest problem has been addressed, your plant will recover and regrow new foliage.
If your Venus flytrap has been ravaged by aphids or spider mites to the point that it is black and decaying, you will have to dispose of the plant and start over.
In the wild, Venus flytraps thrive in bogs which typically consist of spongy, partially decayed plant matter called peat, which is naturally acidic and deficient in nutrients.
To replicate these conditions you can use peat moss or coconut coir mixed with an equal part coarse sand.
You have to be careful, however, since some peat and sphagnum moss are milled and can become contaminated with salt. To remove any salts that may have been introduced during the milling process, add gardening-grade charcoal.
Alternatively, make sure to purchase a potting mix made specifically for carnivorous species, such as this one available via Amazon.
Carnivorous Plant Soil Mix
If you are growing your plants in regular potting soil, or a mix with a pH that isn’t between 3.9 and 4.8, they can start to wither and the traps turn black.
Additionally, Venus flytraps are highly sensitive to fertilizer and any media high in nutrients or applications of fertilizer will cause the roots to burn, and the foliage to darken as it dies.
4. Too Much or Too Little Food
In the wild, Venus flytraps catch their prey by capturing them in their traps before digesting them slowly. Hopefully, your plant doesn’t have a ton of live prey to catch while living in your home!
This means that you have to provide them with sustenance. However, feeding a Venus flytrap incorrectly can cause them to turn black and even die.
You’ll need to give them small, soft-bodied insects like crickets, flies, and mealworms. Bigger insects such as cockroaches or large spiders that don’t fit fully inside the trap aren’t able to be digested and will rot.
During the growing season, you should feed your plant one insect every four to six weeks. Only feed half of the traps at one time, or else you risk overfeeding which can kill the plant.
Never, ever feed your Venus flytrap raw meat! This can introduce disease-causing pathogens and waste your plant’s energy, which will ultimately cause it to turn black and die.
5. Water Issues
Venus flytraps are very sensitive to contaminants or nutrients in water. Their roots will burn if you use tap water or bottled water, which will result in the foliage turning black and dying.
When you water, be sure to use collected rainwater or distilled water. Tap water is treated and can contain high amounts of chlorine or fluoride, and bottled water generally contains minerals that your plant will not appreciate.
Overwatering or underwatering can also cause the foliage to blacken. The former can cause root rot, which will eventually kill the plant, and the latter will cause it to wilt and die.
You want to aim to provide consistent moisture without making the potting medium soggy or waterlogged. Bottom watering can help you get the balance just right.
Keep Calm and Flytrap On
Now you know what to do if your Venus flytrap has started to turn black.
Start by checking how much light your plant is receiving and the potting media that it’s living in before re-examining your watering and feeding schedule. And don’t forget to inspect for pests!
Are you growing Venus flytraps? Have you had a problem with them turning black? Let us know in the comments section below!
And if you want to learn more about carnivorous plants, check out these guides next:
