Lecanopteris Ferns - The Incredible Lettuce Fern and Its Symbiotic Relationship with Ants

An Introduction to the Fascinating Lecanopteris Fern

The lecanopteris fern, scientifically known as Lecanopteris mirabilis, is an incredible and fascinating plant species. This epiphytic fern has unique characteristics and relationships with ants that make it stand out in the plant world.

What is Lecanopteris?

Lecanopteris is a genus of ferns in the family Polypodiaceae. There are approximately eight known species in this genus, all of which are native to tropical regions of Southeast Asia, including areas of Thailand, Malaysia, Indonesia, the Philippines, and New Guinea.

The most well-known and widely cultivated species is Lecanopteris mirabilis, also known as the lettuce fern or Miracle fern. This species is characterized by its thin, undivided fronds that can grow up to 1 meter long. The fronds emerge in a rosette pattern from a short rhizome covered in pale brown hairs.

Key Characteristics of Lecanopteris Ferns

Here are some of the defining features and characteristics of Lecanopteris mirabilis:

• Epiphytic growth habit - Unlike most ferns that grow in soil, Lecanopteris grows on other plants and surfaces like tree trunks and branches.
• Rhizomatous growth - New fronds emerge from a short, creeping rhizome covered in rusty hairs.
• Simple, entire fronds - The fronds are not divided into leaflets but are one continuous undivided leaf blade.
• Rosette pattern - The long arching fronds radiate outwards in a circular rosette pattern.
• Slow growth - Lecanopteris is a slow growing fern, only producing a few new fronds per year.
• Myrmecophytic symbiosis - Many species form a symbiotic relationship with ants.

Myrmecophytic Symbiosis with Ants

One of the most fascinating things about Lecanopteris ferns is their symbiotic relationship with ants. Lecanopteris is classified as a myrmecophyte, meaning it forms a mutualistic association with ants.

The fern provides shelter and housing for the ants underneath its rhizome. The underside of the rhizome has cavities and tunnels that create a nesting space for the ants. In return, the ants defend the fern against herbivores and parasites. The ants may also provide nutrients to the fern in the form of waste products from their nest.

Ants are aggressively protective of their home inside the Lecanopteris rhizome. They will attack anything that disturbs or damages the fern. This symbiotic relationship benefits both species - the ants gain a secure nest site and the fern gains a personal army of defenders!

Cultivation and Care

Due to its unique appearance and growth habits, Lecanopteris has become a popular ornamental fern grown by houseplant enthusiasts and professional growers. Here are some tips for successfully growing this species:

• Provide bright, filtered light or partial shade. Lecanopteris thrives in humid, tropical conditions.
• Use an orchid potting mix or bark substrate. Good drainage is essential.
• Mist the fronds frequently to maintain high humidity.
• Mount on a plaque or tree fern slab to emulate its natural epiphytic growth.
• Keep the root zone moist but not saturated.
• Feed monthly during the growing season with a diluted orchid fertilizer.
• Prune any dead or damaged fronds to keep the plant looking tidy.
• Propagate new plants by dividing the rhizome or from spores.

Interesting Facts About Lecanopteris

• The name Lecanopteris comes from the Greek words lekano meaning "basin" and pteris meaning "fern", referring to the shape of the fronds.
• Lecanopteris is sometimes called the "lettuce fern" due to the shape and texture of its ruffled fronds resembling lettuce leaves.
• The ants that most commonly inhabit Lecanopteris rhizomes are species of Crematogaster, which fiercely protect their fern host.
• Lecanopteris is thought to be the oldest known plant with an ant symbiotic relationship, with this mutualism evolving around 34 million years ago.
• The unicellular green algae Trentepohlia lives within the tissues of Lecanopteris fronds and gives them an orange coloration.
• Lecanopteris grows best when the rhizome is kept at a constant temperature between 68-86°F (20-30°C).
• In its native Southeast Asia, Lecanopteris grows in tropical lowland forests and on trees and rocks near streams and waterfalls.

Growing and Caring for Lecanopteris Houseplants

The unique lettuce fern Lecanopteris makes a fascinating and statement-making addition to any houseplant collection. With its huge arching fronds and symbiotic relationship with ants, this epiphytic fern is sure to be a conversation starter.

While it can be challenging to cultivate, Lecanopteris can thrive indoors if given the proper care and conditions. Here is a deep dive into how to successfully grow these amazing ferns at home.

Light Requirements

Lecanopteris ferns prefer bright, filtered light similar to what they would receive in the dappled understory of a tropical forest. When growing Lecanopteris indoors, aim for a spot that receives indirect light for most of the day.

A south or west-facing window is ideal, although east or even north-facing windows can work as well provided they get at least a few hours of sun. Direct hot midday sun should be avoided as this can scorch the sensitive fronds.

If natural light from a window is not possible, you can also use grow lights to illuminate your Lecanopteris. LED full spectrum grow lights positioned 12-18 inches above the fern will provide beneficial light for photosynthesis while keeping the leaves from overheating.

Ideal Temperature for Lecanopteris

Warm and humid is the name of the game when it comes to lecanopteris temperature preferences. Ideal growing temperatures for these tropical ferns are between 70-85°F (21-29°C) during the day and around 65-75°F (18-24°C) at night.

Avoid exposing your Lecanopteris to temperatures below 60°F (15°C) for any prolonged time, as this can damage the foliage. A room with normal indoor household temperatures maintained by heating and cooling systems should provide an adequate temperature range.

You can also use a humidifier near your Lecanopteris to boost moisture in the air and create the tropical environment it thrives in. Maintaining 50-60% relative humidity around the fern is recommended.

Soil and Potting Mix

Lecanopteris has very fine hair-like roots that demand an open, porous potting mix that won’t stay overly wet or compacted. The ideal substrate is one that provides plenty of aeration and free-draining properties.

A specialized orchid potting blend is a great choice for Lecanopteris as it contains chunks of bark, perlite, charcoal and other chunky amendments. You can also make your own mix using equal parts orchid bark, perlite, peat moss or coco coir.

Terracotta orchid pots or wire baskets are preferred over standard plastic planters. This allows maximum air circulation around the roots. Mounting the fern on a slab of tree fern, cork or wood is another option that mimics its natural epiphytic growth.

Watering Lecanopteris

Lecanopteris prefers moist but not soggy soil at all times. Allow the top 1-2 inches of the potting mix to dry out between waterings then flood the container with room temperature water until it drains freely from the bottom.

Avoid both under and over-watering this fern. Drought stress will cause fronds to lose color and wilt while constant saturation will cause root rot. Check soil moisture with your finger to gauge when to water.

Increase watering frequency slightly during the active growth period in summer. In winter, allow the soil to become a bit drier between waterings but don’t let it stay completely dry for extended time.

Misting the fronds a few times per week or using a pebble tray filled with water can help provide extra humidity if the air is very dry.

Fertilizer Needs

To fuel all that lush foliage growth, Lecanopteris benefits from regular fertilizing during the spring and summer. Use a balanced orchid fertilizer diluted to half or quarter strength or a products designed specifically for epiphytic ferns.

Fertilize every 2-4 weeks when the fern is actively growing and producing new fronds. You can discontinue fertilizer or reduce frequency in fall and winter when growth slows.

Excess fertilizer can burn roots and build up to toxic levels in the potting mix. Always flush the growing medium with plain water after applying fertilizer to prevent salt accumulation.

Common Pests and Problems

When grown correctly indoors, Lecanopteris is relatively pest and disease free. But there are a few potential issues to watch out for:

• Root rot - Caused by overwatering or slow-draining soil. Improve drainage and allow soil to dry adequately between waterings.
• Mealybugs and spider mites - Treat with horticultural oil or insecticidal soap sprays.
• Scale insects - Wipe off with alcohol dipped cotton swabs or use neem oil.
• Fading fronds - Can indicate insufficient humidity, lighting, or nutrition.

Promptly trim off any fronds that are badly damaged, diseased or infested with pests. This helps keep the plant healthy and encourages lush new growth.

Propagating and Repotting Lecanopteris

This unique fern can be propagated by division when the rhizome produces new offsets. You can also try propagating lecanopteris from spores, although this is trickier and requires very sterile conditions.

Dividing the Rhizome

Dividing an overgrown lecanopteris specimen is the most reliable propagation method. Wait until the plant is at least 2-3 years old and has developed multiple crowns and offsets.

Carefully remove the fern from its pot and use a sterile tool like a knife or single-edge razor to divide the rhizome into sections, with at least 3-5 fronds per division.

Let divisions dry out for a few days before potting up individually in a fresh orchid potting mix. Keep them warm, humid, and shaded while they develop new roots and establish.

Spore Propagation

You can also propagate new lecanopteris ferns from spores collected from the underside of mature fronds. Use a clean paper envelope to catch the dust-like spores once they are released.

Sow spores thinly on the surface of sterile potting mix and enclose under a plastic dome or bag to maintain constant 100% humidity. Place in bright indirect light and wait several weeks for tiny gametophyte plants to develop.

Gradually acclimate plants to lower humidity as they grow. This process takes many months and requires diligent care but can produce many new plants from just a few spores.

Repotting Mature Plants

Repot lecanopteris every 2-3 years in spring when new growth emerges. Trim off any dead roots and divide congested rhizomes. Old potting mix should be discarded and replaced with a fresh, sterile orchid blend.

Choose a pot that is 2 inches larger than the current container or upsize if the roots are crowded. Pack soil gently around the rhizome and water thoroughly after repotting. Keep the fern shaded for a few weeks while it re-establishes.

Fun Varieties of Lecanopteris to Grow

While Lecanopteris mirabilis is the most common and readily available, there are a few other interesting species and varieties of these unusual ferns to look out for:

• Lecanopteris sinuosa - Wavy leaf edges give the fronds a ruffled, crinkly look.
• Lecanopteris crustacea - Fronds emerge in a tight cylindrical rosette shape.
• Lecanopteris darnaedii - Extra large fronds can reach up to 2 meters long!
• Crested forms - Mutated fronds grow densely packed and layered.
• Variegated forms - Leaves feature yellow or white striping and patterns.

These interesting varieties may be harder to find, but are worth seeking out for collectors interested in unique houseplants. With a little luck and proper care, the fabulous lettuce fern Lecanopteris can thrive as a standout part of your indoor plant collection!

FAQs

Why are the fronds of my Lecanopteris turning brown or yellow?

This can be caused by too much light, low humidity, overwatering, or inadequate fertilization. Try moving the fern to a shadier spot, misting more often, letting the soil dry out further between waterings, and applying a balanced fertilizer.

What type of soil does the lettuce fern need?

Lecanopteris requires a very fast draining potting mix, such as an orchid bark blend. The roots will rot if kept too wet. Add perlite, charcoal, or small lava rocks to improve drainage.

Should I mist my Lecanopteris fern?

Yes, frequent misting is highly beneficial for Lecanopteris. The leaves readily absorb moisture from the air and misting helps maintain the high humidity these tropical ferns need to thrive.

Why is my lettuce fern not growing or producing new fronds?

Lack of new growth usually indicates the fern is not getting enough light. Try a brighter location filtered from direct sun. Insufficient nutrition can also cause slow growth, so apply a balanced fertilizer at half strength.

What is the best way to propagate my Lecanopteris?

Dividing the rhizome when the plant is mature enough is the most reliable way to get new Lecanopteris plants. Take sections with 3-5 fronds and pot up individually in orchid mix. Keep warm, humid and shaded.