Everything you need to know about growing carnivorous plants.

Common species of carnivorous plants

Carnivorous plants come in several species, each with its own characteristics and requirements. Among the most common are Dionaea, Nepenthes and Sarracenia, which attract both beginner and experienced gardeners.

Dionaea (Dionaea muscipula)

The Venus Flytrap, commonly known as Venus’s jaw, is undoubtedly the most iconic carnivorous plant. It originates from bogs on the East Coast of the United States. Its popularity rests on its traps that snap shut quickly on unsuspecting insects. They are jaw-shaped with sensory cilia. The Dionaea can eventually flower on long stalks with white flowers. These indoor plants require a nutrient-poor substrate and plenty of light. They are ideal for beginner gardeners due to their relatively simple care and spectacular trapping mechanism.

Their main needs

• Light: needs full sun for healthy growth.
• Water: prefer a consistently moist substrate. Use rainwater or demineralised water.
• Substrate: peat-based mix with no additives and perlite or sand.
• Temperature: tolerate a range of temperatures, but prefer temperate to warm conditions.

Nepenthes

Nepenthes, or pitcher plants, are known for their cup-shaped traps filled with digestive fluid to drown and digest prey. These exotic houseplants are native to tropical regions of Asia, offering a wide diversity of sizes, shapes and colours and are suited to a wide range of habitats. The traps are cup-shaped, hanging, often coloured and sometimes very large. They prefer warm and humid environments, making them ideal for a greenhouse or well-lit conservatory. Their cultivation can be more demanding, but they reward patient gardeners with their extraordinary beauty.

Their main needs

• Light: bright, but indirect, light, sheltered from direct sun.
• Humidity: require high humidity, often above 60%.
• Substrate: well-aerated and draining mix, typically based on peat, bark and perlite.
• Temperature: prefer warm, constant temperatures.

Sarracenia

Sarracenia, or American pitcher plants, are distinguished by their long tubular leaves that trap insects, with an operculum covering the opening. Native to North American marshes, they display a wide variety of sizes, shapes and colours. The traps use a combination of nectar, colour and gravity to capture prey. These carnivorous plants are adaptable to a range of climates and can be grown both outdoors and as houseplants. They require direct sun exposure and a specific substrate, often peat and sand. Sarracenia are prized for their natural elegance and colourful flowers, adding a touch of sophistication to any gardening space.

Their main needs

• Light: full sun for optimal growth.
• Water: they prefer a constantly moist substrate. Use rainwater or demineralised water.
• Substrate: peat-based and perlite or sand mix without additives.
• Temperature: tolerate a range of temperatures but prefer temperate conditions.

Long-leaved Sarracenia with colourful opercula enjoy full sun

Optimal growing conditions

To successfully cultivate carnivorous plants, it is essential to understand and replicate as closely as possible their natural habitat. These plants have specific requirements in terms of light, humidity, substrate and watering.

Light

Light plays a crucial role in the growth and health of carnivorous plants. Most of these plants, including Dionaea and Sarracenia, require direct sunlight for several hours each day. A lack of light can lead to weakened traps and less vigorous growth. For indoor plants, a position near a well-lit window or the use of grow lights may be necessary.

Humidity

Humidity is another key factor, particularly for Nepenthes and other tropical carnivorous plants. These plants thrive in high-humidity environments. It may be useful to use a humidifier or place the plants in terrariums to maintain the required humidity. Plants such as Sarracenia, however, adapt well to less humid conditions.

Substrate

The choice of substrate is essential for carnivorous plants. They generally prefer a nutrient-poor soil, often a mix of turf without additives and of perlite or of sand. It is crucial to avoid enriched potting mixes or standard substrates for houseplants, as they can be harmful to these specialist species.

Watering

Watering should be carried out with care. Tap water, often high in minerals, is not recommended. It is preferable to use rainwater or demineralised water. Carnivorous plants prefer a consistently moist but not waterlogged medium. Overwatering can lead to root rot, while underwatering can stress the plant.

Dionaea and their ciliate jaws are fairly easy to grow.

Daily care and maintenance

Carnivorous plants, although they may seem demanding, can thrive with proper care. Understanding their specific daily-care needs such as fertilisation, repotting and disease prevention is essential to keep these houseplants healthy.

Care routine

The daily care routine for carnivorous plants is fairly simple. It is important to regularly check the substrate moisture and ensure adequate light exposure. Dead or damaged leaves should be removed to prevent rot and infestations. It is also advisable to monitor trap activity to ensure they are functioning correctly.

Fertilisation

Unlike ordinary houseplants, carnivorous plants generally do not require fertilisation frequently. In fact, over-fertilisation can be detrimental to them. If necessary, very dilute fertilisation can be applied directly to the traps or leaves, but this should be done with care and rarely.

Repotting

Repotting is an important step in caring for carnivorous plants. It is generally recommended to repot these plants every one to two years to refresh the substrate and prevent the soil from becoming compacted. Repotting should be carried out carefully, using appropriate substrate and avoiding excessive disturbance of the delicate roots.

Disease prevention

Carnivorous plants can be susceptible to various health issues, including insect infestations and fungal diseases. Regular inspection of the plants to detect any signs of stress or disease is crucial. If a problem occurs, it is important to treat the plant with products suited to carnivorous plants, as some standard houseplant treatments can be harmful to them. See the next chapter for more details.

Nepenthes and their swollen urns are grown in suspension

Common diseases and parasites

Carnivorous plants, despite their hardy nature, can be susceptible to a range of diseases and parasitic infestations. Understanding these problems and implementing appropriate preventive and curative measures is essential to maintaining the health of these unique houseplants.

Fungal rot

Fungal rot is one of the most common diseases in carnivorous plants. It is often caused by excessive humidity and poor substrate drainage. The symptoms include discolouration of the leaves and traps, as well as soft tissue decay of the plant. To prevent this disease, it is crucial to maintain a proper humidity balance and ensure adequate drainage. In case of infection, remove the affected parts and treat the plant with an appropriate fungicide.

Insect infestations

Although carnivorous plants are themselves insect predators, they can sometimes be infested by certain pests. Aphids and mealybugs are the most common. These pests feed on the plant sap, weakening their growth and vitality. Signs of infestation include slowed growth, sticky leaves, or the presence of small insects on the plant. Biological control methods may be required to tackle these pests.

→ Read our article on how to get rid of aphids

→ Read our article on how to treat mealybugs

Moulds and algae

Moulds and algae can also affect carnivorous plants, particularly in conditions of poor air circulation and high humidity. These organisms can cover the traps and leaves, hindering photosynthesis and the plant’s ability to capture its prey. Good ventilation and reducing humidity are often sufficient to prevent these problems. If an infestation occurs, it may be necessary to carefully clean the plant and adjust growing conditions.

Viral and bacterial diseases

Although less common, some carnivorous plants can be affected by viral or bacterial diseases. These diseases can be difficult to treat and often manifest as leaf spots, deformation of the traps or abnormal growth. Prevention is best, by avoiding overcrowding of plants and maintaining strict hygiene when handling and repotting.