Cryptanthus - Earth Star: Growing and Care

Botany and description

The Cryptanthus belongs to the large Bromeliaceae family, which includes many exotic plants, sometimes epiphytic, grown indoors (Bromellia, Guzmania, Tillandsia…) and a more familiar 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 French, it’s called Cryptanthe, but it’s also nicknamed “earth star plant” or “starfish plant”, names that perfectly evoke the star-shaped form of its leaves that seem to radiate just above the ground.

In its natural habitat, 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 dappled light under the canopy. It’s precisely this ability to adapt to indirect light conditions and its tolerance to drier air that make it such a popular houseplant. Its spectacular foliage, often striped or tinged with pink, red or green, adds a graphic and colourful touch to interiors, while requiring minimal maintenance.

Among the most common Cryptanthus species in cultivation, 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’s prized for its slender foliage with vibrant colours, often striated with green, pink or red. Among its best-known cultivars are:

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

The Cryptanthus acaulis stands out with its broader, slightly undulate leaves. It’s often chosen for its subtle silvery-green hues. Notable varieties include:

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

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

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

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

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

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

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

?Changing foliage: Cryptanthus leaves change colour depending on light. Indeed, some Cryptanthus varieties see their colours become more intense when they receive more indirect light. Pink or red tones thus become more vivid.

Cryptanthus flowering is discreet and often overlooked. Small tubular white or slightly bluish flowers appear at the heart of the rosette. This flowering isn’t spectacular, but it marks an important stage in the plant’s life cycle. Indeed, like many bromeliads, Cryptanthus is semelparous, meaning it dies after flowering. However, this end isn’t abrupt: the plant takes several months, even a year, before completely fading. During this time, it produces offsets, 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, Cryptanthus may produce small dry fruits containing seeds, although this fruiting is discreet and uncommon 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 growing medium

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

Choosing the pot

Since the Cryptanthus has a small root system, it doesn’t need a large pot. A container 10 to 15 cm in diameter is more than enough, especially for young plants or offsets. Opt for a wide, shallow pot to accommodate its rosette growth. Ensure the pot has drainage holes to prevent water stagnation, which could lead to root rot.

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

A small pot is sufficient for the Cryptanthus

Ideal growing medium

The Cryptanthus prefers light, well-draining, slightly acidic growing mediums. You can prepare a homemade mix with:

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

For better aeration, you can add some sphagnum moss or small pieces of pine bark.

☀️Light

The Cryptanthus prefers bright, indirect light. Near an east or west-facing window is ideal. It tolerates low-light rooms fairly well. In a terrarium, place it near a natural light source or use a grow light if light is insufficient.

?️Temperature

This tropical plant loves warmth! The ideal temperature ranges 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.

? Humidity

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

• Mist its leaves lightly with non-calcareous water,
• Place the pot on a tray of damp clay pebbles,
• In a terrarium, humidity is naturally higher since it’s a closed medium, so frequent watering isn’t necessary.

? Planting steps

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

In a terrarium, you can add decorative elements like moss, pebbles, or small pieces of wood to create a lovely natural display.

Cryptanthus bipinnatus ‘Ruby Red’

Growing and caring for Cryptanthus

The cultivation and care of Cryptanthus are relatively simple, making it an ideal houseplant, even for beginners. Here are all the tips to look after it properly.

? Watering

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

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

Native to tropical forests, Cryptanthus appreciates high ambient humidity.

• Regular misting of its leaves with soft water is beneficial, especially in winter when indoor air becomes dry due to heating.
• You can also place the pot on a bed of moist clay pebbles to maintain good humidity levels.
• However, avoid soaking the centre 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 houseplants or tropical plants, diluted to half the recommended dose, is sufficient.
• In autumn and winter, fertilising is not necessary.

✂️ 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 carefully detach the offsets (suckers) that appear around it 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 offsets, wait until they reach at least a third of the size of the mother plant before separating and replanting them (see propagation section).

⚠️ Precautions to take

• Avoid overwatering, as the shallow roots are prone to rot.
• Protect from cold draughts, 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 Cecilia Alexander)

Potential parasitic and disease issues

The Cryptanthus is generally a robust plant, but like all houseplants, it can be vulnerable to certain parasitic and diseases, especially if growing conditions are not optimal. Here are the main problems 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 ventilation.
   • 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 young leaves or around the rosette. Sticky and deformed leaves.
   • Causes: excess humidity and poor ventilation.
   • Treatment: spray with a soapy water mixture or black soap. Aphids can also be removed with a gentle jet of water.
3. Spider Mites
   • Symptoms: pale leaves with small yellow or brown spots, sometimes accompanied by fine webbing.
   • Causes: overly dry air and excessive heat.
   • Treatment: increase humidity by misting regularly. Clean the leaves and, if necessary, apply a natural miticide.
4. Thrips
   • Symptoms: small silver streaks on the leaves, discoloured appearance, deformed leaves.
   • Causes: dry air and high temperatures.
   • Treatment: mist regularly, isolate the plant, and use an organic insecticidal if needed.

Common Diseases

1. Root Rot
   • Symptoms: yellowing leaves that become soft, and an unpleasant odour from the substrate.
   • Causes: overwatering, overly compact or poorly draining substrate.
   • Prevention and Treatment:
     • use a well-draining substrate.
     • water moderately and remove stagnant water from the saucer.
     • if rot occurs, remove the plant, trim damaged roots, and repot in fresh substrate.
2. Collar Rot
   • Symptoms: base of the plant turning black and soft.
   • Causes: stagnant water in the rosette or overly moist substrate.
   • Prevention and Treatment:
     • avoid pouring water directly into the centre of the plant.
     • ensure good drainage.
     • if infected, it is often difficult to save the plant. Take healthy offsets to replant.
3. Fungal Spots
   • Symptoms: brown or black spots appearing on the leaves.
   • Causes: excess humidity, poor ventilation.
   • Prevention and Treatment:
     • space out watering.
     • remove affected leaves.

Prevention Tips

• Maintain good humidity, but avoid excess water.
• Use a light and well-draining substrate.
• Avoid cold draughts and sudden temperature changes.
• Clean the leaves regularly to prevent dust buildup.
• Monitor the plant closely and act quickly at the first sign of parasites or diseases.

Learn more in our article Cryptanthus: Diseases, Parasites, and Common Problems of This Houseplant.

Propagation of Cryptanthus

Propagating Cryptanthus is quite straightforward and is mainly done through its offsets, also known as suckers. This method of propagation is natural, as the mother plant spontaneously produces young shoots around it before withering after flowering. This technique helps preserve the characteristic features of the varieties, unlike sowing, which can produce plants with variable patterns and colours. Here’s a step-by-step guide to successfully propagate your Cryptanthus.

• Observe the mother plant: after flowering, the Cryptanthus begins to produce small offsets at the base of the rosette. These shoots resemble tiny miniature stars attached to the main plant.
• Wait for the right time: it’s important to let the offsets grow before removing them. They should measure at least 5 to 8 cm or reach a third of the size of the mother plant. This ensures they are robust enough to survive on their own.
• Prepare the materials:
  • a clean pair of secateurs or a sharp, disinfected knife.
  • small pots with a suitable substrate (a mix of light compost, sand, and turf).
  • non-calcareous water.
• Detach the offsets
  • carefully remove the mother plant from its pot to better access the offsets.
  • cleanly cut the offset at its base, where it attaches to the mother plant. Be careful not to damage any young roots if they are already present.
• Plant the offsets
  • fill a small pot with a light, well-draining substrate (compost + perlite).
  • plant the offset by slightly burying its base without covering the rosette.
  • lightly firm the soil around it to keep the young plant in place.
• Initial care after planting
  • water lightly to moisten the substrate without waterlogging it.
  • place the pot in a warm, bright spot, but out of direct sunlight. A temperature around 22 to 26°C will encourage rooting.
  • maintain good ambient humidity with regular misting or by placing the pot under a cloche or in a terrarium.
• Monitor the recovery
  • the first roots develop within four to five weeks.
  • once growth accelerates and new leaves appear, you can resume standard care.

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

How to showcase a starfish plant?

? Types of interiors suited to Cryptanthus

Modern and minimalist interiors

Its geometric shapes and vibrant 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 perfectly into dense plant décor, mingling with tropical plants, wicker baskets and natural materials. Marbled-pattern species like Cryptanthus zonatus ‘Zebra’ add interesting textures among more classic foliage.

Industrial décor

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

? Pot and terrarium styles to showcase Cryptanthus

Ceramic or raw concrete pots

Ideal for brightly coloured varieties like ‘Pink Starlite’ or ‘Ruby’, which stand out against understated materials. Geometric or clean-lined pots accentuate its star-shaped habit.

Open or semi-closed terrariums

Cryptanthus loves humidity, making it perfect for terrariums. Paired with moss, pebbles and pieces of driftwood, it creates a mini tropical garden. Species like Cryptanthus zonatus work well in these compositions.

Hanging pots or wide shallow bowls

Placed in a shallow bowl or hanging pot, its rosette habit is beautifully showcased. Glass or glazed terracotta pots enhance its graphic appeal.

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

Natural material planters

For a bohemian look, a rattan, wicker or jute planter adds a warm touch that contrasts with its structured foliage.

✨ Décor tip

Grouping several Cryptanthus of different colours and varieties in the same container or in several coordinated small pots creates a striking graphic composition. Playing with heights, textures and pot materials helps highlight their natural beauty.