Cryptanthus - Earth Star: How to Grow and Care for It

Botany and Description

The Cryptanthus belongs to the large family of Bromeliaceae, a family that includes a number of exotic plants, sometimes epiphytes, grown indoors (Bromellia, Guzmania, Tillandsia…) and a more well-known plant: the pineapple (Ananas comosus). Its genus name comes from the Greek kryptos meaning “hidden” and anthos meaning “flower”, a poetic reference to its small, discreet flowers nestled at the heart of its foliage. In English, it is called Cryptanthe, but it is sometimes also nicknamed “starfish plant” or “earth star”, names that perfectly evoke the star-shaped form of its leaves that seem to radiate close to the ground.

In its natural habitat, the Cryptanthus thrives in the humid tropical forests of Brazil. Unlike many of its bromeliad cousins that live attached to trees (epiphytic plants), it prefers to spread across the forest floor, benefiting from the ambient humidity and the dappled light under the canopy. It is precisely this ability to adapt to indirect light conditions and its tolerance for drier air that make it a very popular indoor plant. Its spectacular foliage, often striped or tinged with pink, red, or green, adds a graphic and colourful touch to interiors, while requiring little maintenance.

Among the Cryptanthus species most commonly cultivated, three stand out particularly for their beauty and diversity: Cryptanthus bivittatus, Cryptanthus acaulis, and Cryptanthus zonatus.

The Cryptanthus bivittatus is the most popular species. It is appreciated for its elongated foliage with vibrant colours, often striated with green, pink, or red. Among its most well-known cultivars, we find:

• ‘Pink Starlite’ with its stunning bright pink leaves edged with green,
• ‘Ruby’, which displays deep red tones,
• ‘Earth Star’, a classic with star-shaped foliage in shades of pink and green.

The Cryptanthus acaulis is distinguished by its broader and slightly undulate leaves. It is often chosen for its subtle shades of silvery green. Among its notable varieties, we can mention:

• ‘Green Star’, with intense green foliage,
• ‘Silver Star’, with silvery reflections that beautifully capture the light.

As for the Cryptanthus zonatus, it charms with its marbled and striped patterns, giving an almost animal-like effect to its foliage. Cultivars such as:

• ‘Zebra’, with its white and green stripes reminiscent of a zebra’s coat,
• ‘Cascade’, which combines grey and green tones with a more pendulous habit, are particularly appreciated for their originality.

Colours and stripes are among the great attractions of Cryptanthus (photo bottom right by Mokkie-Wikimedia Commons)

The Cryptanthus is a plant with a compact and spreading habit that naturally forms a dense, flattened rosette (no more than 15 cm tall). Its star-arranged leaves extend close to the ground. Some species, like the Cryptanthus bivittatus, have narrower, upright leaves, while others, like the Cryptanthus zonatus, develop broader and slightly undulate leaves.

Its root system is quite reduced and superficial. The roots primarily serve to anchor the plant in the soil rather than to absorb water and nutrients, as the Cryptanthus mainly draws its moisture from the surrounding air and the dew deposited on its leaves. This is why it prefers well-drained, light substrates and enjoys regular misting.

The foliage is undoubtedly the major asset of the Cryptanthus. Its stiff and tough leaves are often edged with fine teeth or small, discreet thorns. They come in spectacular colour palettes: deep green, bright pink, intense red, bronze, silver, sometimes even marbled or striped with white. Varieties like ‘Pink Starlite’ offer bright pink shades, while ‘Zebra’ entices with its contrasting stripes. This decorative foliage remains attractive all year round.

A foliage that changes: the colours change according to the light in Cryptanthus. Indeed, some varieties of Cryptanthus see their colour become more intense when they receive more indirect light. The pink or red hues thus become more vivid.

The flowering of the Cryptanthus is discreet and often little noticed. Small tubular white or slightly bluish flowers appear at the heart of the rosette. This flowering is not spectacular, but it marks an important stage in the life cycle of the plant. Indeed, like many bromeliads, the Cryptanthus is semelparous, meaning it dies after flowering. However, this end is not abrupt: the plant takes several months, or even a year, before completely fading. During this time, it produces offshoots, called basal shoots or suckers, which will take over. These young plants can be separated and replanted to prolong the presence of this “earth star” in the home.

After flowering, the Cryptanthus can produce small dry fruits containing seeds, although this fruiting is discreet and infrequent in indoor cultivation. These seeds, nestled at the heart of the rosette, are rarely used for propagation, as their germination is slow and unpredictable.

Cryptanthus zonatus ‘Elaine’

Pot and Substrate

The Cryptanthus is a plant that thrives in pots, but also in terrariums. To plant it properly and see it flourish, here are all the tips to follow!

Pot Selection

Since the Cryptanthus has a less developed root system, it doesn’t require a large pot. A container with a diameter of 10 to 15 cm is quite sufficient, especially for young plants or offshoots. Choose a wide and shallow pot to support its rosette growth. Ensure that the pot has drainage holes to prevent any water stagnation, which could lead to root rot.

In a terrarium, it will enjoy open or semi-closed models to maintain good humidity without excess.

A small pot is enough for the Cryptanthus

Ideal Substrate

The Cryptanthus prefers light, draining, and slightly acidic substrates. You can prepare a homemade mix with:

• 1/2 tropical or green plant compost,
• 1/4 coarse sand or perlite for drainage,
• 1/4 blonde turf or coconut fibre for acidity and moisture retention.

For more aeration, you can add a bit of sphagnum moss or small pieces of pine bark.

☀️Exposure

The Cryptanthus prefers bright, but indirect light. A spot near an east or west-facing window is ideal. It tolerates low-light rooms quite well. In a terrarium, place it near a natural light source or use a horticultural lamp if light is lacking.

?️Temperature

This tropical plant loves warmth! The ideal temperature is between 18°C and 27°C. It does not tolerate cold drafts or temperatures below 15°C. In winter, keep it away from poorly insulated windows and cold sources.

? Ambient Humidity

The Cryptanthus thrives in humid environments, especially indoors where the air is often dry. The ideal humidity is around 60 to 80%. To maintain this humidity:

• Lightly mist its leaves with non-limestone water,
• Place the pot on a bed of moist clay pebbles,
• In a terrarium, the humidity is naturally higher because it’s a closed environment, so frequent watering isn’t necessary.

? Planting Steps

• Choose a pot with good drainage, or a terrarium.
• Lay a layer of clay pebbles or small stones at the bottom of the pot to prevent excess water.
• Prepare a well-draining substrate and fill the pot, leaving a small hollow in the center.
• Gently repot your Cryptanthus and carefully free the roots if they are too tight.
• Place the plant in the center of the pot and cover the roots without compacting the substrate too much.
• Water lightly to moisten the soil without soaking it.
• Place it in a bright spot, but away from direct sunlight.

In a terrarium, you can add decorative elements like mosses, pebbles, or small pieces of wood to create a beautiful natural decor.

Cryptanthus bipinnatus ‘Ruby Red’

Cultivation and Care of Cryptanthus

Growing and caring for Cryptanthus is relatively straightforward, making it an ideal indoor plant, even for beginners. Here are all the tips you need to take good care of it.

? Watering

Cryptanthus prefers a slightly moist substrate, but never waterlogged. Its root system is shallow, so it is sensitive to excess water.

• During the growth period (spring and summer), it is advisable to water moderately, allowing the substrate to dry out slightly between waterings.
• In winter, when growth slows down, waterings should be spaced out. Watering every 2 to 3 weeks may suffice, depending on the ambient temperature.
• Preferably use soft water (rainwater or filtered water) at room temperature.

Originally from tropical forests, Cryptanthus appreciates a high ambient humidity.

• A regular misting of its leaves with soft water is beneficial, especially in winter when indoor air becomes dry due to heating.
• It is also possible to place the pot on a bed of moist clay pebbles to maintain good humidity levels.
• However, avoid soaking the heart of the rosette to prevent fungal diseases.

Fertilisation

Cryptanthus is not very demanding, but a little boost can enhance its foliage.

• During the growth period (spring/summer), a monthly application of liquid fertiliser for green or tropical plants, diluted to half the recommended dose, is sufficient.
• In autumn and winter, it is not necessary to fertilise.

✂️ Pruning

Cryptanthus does not require regular pruning. Simply remove damaged or dried leaves at the base to maintain a neat appearance. After flowering, the mother plant will gradually begin to decline. It is then recommended to gently detach the suckers that appear around to replant them.

Repotting

Cryptanthus grows slowly and its root system is not extensive.

• Repotting every 2 to 3 years is sufficient, or when it seems cramped in its pot.
• Repotting is ideal in spring, in a slightly larger pot, with fresh, well-draining substrate.
• For the suckers, it is advisable to wait until they reach at least one third of the size of the mother plant before separating and replanting them (see propagation point).

⚠️ Precautions

• Avoid excess water, as the shallow roots are prone to rot.
• Protect from cold drafts which can damage the leaves.
• Clean the leaves occasionally with a soft cloth to remove dust and promote the plant’s respiration.

Flowering of Cryptanthus fosterianus (photo by Cecilia Alexander)

Potential Parasitic Issues and Diseases

Cryptanthus is generally a robust young plant, but like all indoor plants, it can be vulnerable to certain parasitic infestations and diseases, especially if the growing conditions are not optimal. Here are the main issues it may face and how to prevent or treat them.

Common Parasites

1. Mealybugs
   • Symptoms: small white, cottony clusters on the leaves and at the base of the rosette.
   • Causes: overly dry atmosphere or lack of air circulation.
   • Treatment: clean the leaves with a cloth soaked in a mixture of water and black soap or 70% alcohol.
2. Aphids
   • Symptoms: small green, black, or yellow insects clustered on the young leaves or around the rosette. Sticky and deformed leaves.
   • Causes: excess moisture and lack of ventilation.
   • Treatment: spray a soapy water mixture or black soap. Aphids can also be removed with a gentle water spray.
3. Red Spider Mites
   • Symptoms: fading leaves, with small yellow or brown spots, sometimes accompanied by fine webs.
   • Causes: overly dry air and excessive heat.
   • Treatment: increase humidity by regularly misting. Clean the leaves and, if necessary, apply a natural acaricide.
4. Thrips
   • Symptoms: small striate marks on the leaves, discoloured appearance, deformed leaves.
   • Causes: dry air and high temperatures.
   • Treatment: regularly mist, isolate the young plant and use an organic insecticidal if necessary.

Frequent Diseases

1. Root Rot
   • Symptoms: leaves turning yellow, becoming soft, and unpleasant odour emanating from the substrate.
   • Causes: excessive watering, overly compact or poorly drained substrate.
   • Prevention and Treatment:
     • use a well-draining substrate.
     • water moderately and empty stagnant water in the saucer.
     • in case of rot, remove the young plant, cut off the damaged roots and repot in a healthy substrate.
2. Collar Rot
   • Symptoms: base of the young plant blackening and becoming soft.
   • Causes: stagnant water at the heart of the rosette or overly moist substrate.
   • Prevention and Treatment:
     • avoid pouring water directly into the heart of the young plant.
     • ensure good drainage.
     • in case of attack, it is often difficult to save the young plant. Take healthy offshoots to replant.
3. Fungal Spots
   • Symptoms: appearance of brown or black spots on the leaves.
   • Causes: excess moisture, lack of air circulation.
   • Prevention and Treatment:
     • space out watering.
     • remove affected leaves.

Prevention Tips

• Maintain good humidity, but avoid excess water.
• Use a light and draining substrate.
• Avoid cold draughts and sudden temperature changes.
• Clean the leaves regularly to prevent dust accumulation.
• Monitor the young plant closely and act quickly if signs of parasites or diseases are detected.

Propagating the Cryptanthus

Propagating Cryptanthus is quite simple and primarily done through its offshoots, also known as suckers. This method of propagation is natural, as the parent plant spontaneously produces young shoots around itself before perishing after flowering. This method helps preserve the characteristics of the varieties, unlike sowing, which can produce plants with variable patterns and colours. Here’s how to proceed step-by-step to successfully propagate this way.

– **Observe the parent plant**: after flowering, the Cryptanthus begins to produce small suckers at the base of the rosette. These shoots resemble tiny miniature stars attached to the main plant.
– **Wait for the right moment**: it is important to **let the suckers grow** before taking them. They should measure **at least 5 to 8 cm** or reach a third of the size of the parent plant. This ensures they are robust enough to survive on their own.
– **Prepare the materials**:
– **a clean pruner or a sharp, disinfected knife**.
– small pots with a suitable substrate (a mix of light potting soil, sand, and turf).
– non-limestone water.

– **Detach the suckers**:
– gently remove the parent plant from its pot to better access the suckers.
– **cut cleanly** **at the base of the sucker**, where it attaches to the parent plant. Be careful not to damage the young roots if they are already present.

– **Plant the suckers**:
– fill a small pot with light, well-draining substrate (potting soil + perlite)
– plant the sucker by slightly burying its base without burying the rosette.
– **lightly press** **around** to keep the plant in place.

– **First care after planting**:
– **water lightly** to moisten the substrate without soaking it.
– place the pot in a warm and bright location, but away from direct sunlight. **A temperature around 22 to 26°C** will promote rooting.
– **maintain good ambient humidity with regular misting** or by placing the pot under a bell jar or in a terrarium.

– **Follow-up care**:
– the first roots develop in four to five weeks.
– once growth accelerates and new leaves appear, it is possible to resume regular maintenance.

*Please note*: Cryptanthus can also be propagated by sowing, but this method is longer and more delicate. It is rarely used by amateurs, as the seeds are difficult to obtain and their germination is slow. Moreover, **sowing may not necessarily produce a plant similar to the parent plant**. Seeds must be sown on a moist and light substrate, maintain a constant temperature (**25°C**), and ensure high humidity. Germination can take several weeks to several months.

How to Highlight a Star of Earth?

Interior Styles Suitable for Cryptanthus

Modern and Minimalist Interiors

Its geometric shapes and bright colours contrast beautifully with clean lines and neutral tones. Varieties like Cryptanthus bivittatus ‘Pink Starlite’, with its bright pink leaves, add a bold splash of colour without cluttering the space.

Bohemian or Urban Jungle Style

Cryptanthus blends seamlessly into a dense plant decor featuring tropical plants, wicker baskets, and natural materials. Species with marbled patterns like Cryptanthus zonatus ‘Zebra’ bring interesting textures among more traditional foliage.

Industrial Decor

In an interior with raw materials (concrete, metal, dark wood), the deep colours of Cryptanthus bivittatus ‘Ruby’ or Cryptanthus acaulis create an elegant contrast. Placed in a raw concrete or black metal pot, it enhances the contemporary spirit of this style.

Scandinavian Ambiance

In interiors with light tones and soft materials, Cryptanthus in gentle shades like ‘Earth Star’ or ‘Green Star’ add a subtle touch of greenery. A pot in white or pastel ceramic, or even in light wood, highlights the simplicity of the plant.

Pot and Terrarium Styles to Enhance Cryptanthus

Ceramic or Raw Concrete Pots

Ideal for varieties with bright colours like ‘Pink Starlite’ or ‘Ruby’, which stand out against understated materials. Geometric pots or those with clean lines accentuate its star-like habit.

Open or Semi-closed Terrariums

Cryptanthus loves humidity, making it a perfect candidate for terrariums. Paired with mosses, pebbles, and some driftwood, it creates a mini tropical garden. Species like Cryptanthus zonatus blend well with these compositions.

Hanging Pots or Wide Dishes

Placed in a shallow dish or a hanging pot, its rosette habit is well showcased. Glass or glazed terracotta pots enhance its graphic nature.

Cryptanthus acaulis at the bottom right, hanging with a Peperomia rosso, a Begonia cleopatrae and Aeschynanthus buxifolius (Photo Peganum-Flickr)

Cache-pots in Natural Materials

For a bohemian decor, a cache-pot in rattan, wicker, or jute adds a warm touch that contrasts with its structured foliage.

✨ Decor Tip

Combining several Cryptanthus of different colours and varieties in the same container or in several coordinated small pots creates a very decorative graphic composition effect. Playing with the heights, textures, and materials of the pots allows you to enhance their natural beauty.