Crocodile Fern

How to care for Crocodile Fern

Light

Crocodile Fern thrives in bright, indirect light that mimics the dappled canopy conditions of its native habitat. A position near a north- or east-facing window is ideal in the UK, or set back from a south- or west-facing window where direct sun is filtered by net curtains or a nearby wall. Direct sunlight will scorch the fronds and cause them to bleach and crisp at the edges. Conversely, very low light slows growth significantly and the characteristic tessellated patterning may become less pronounced.

Watering

The compost should remain evenly moist throughout the growing season but must never become waterlogged, as soggy roots will rot rapidly. Water thoroughly, allowing excess to drain freely, then wait until the top centimetre of compost feels just dry before watering again. Use tepid water that has been left to stand overnight if possible, since cold tap water can shock the roots. Reduce watering frequency in autumn and winter when growth slows, but do not allow the root ball to dry out completely.

Soil and potting

A loose, well-aerated, humus-rich compost is essential to replicate the organic material found in the plant's natural epiphytic growing sites. A suitable mix can be made from two parts peat-free multipurpose compost, one part perlite and one part orchid bark or coarse coco coir. Good drainage is critical; the roots must have access to moisture and air simultaneously. Avoid dense, compacted growing media such as standard potting compost used alone.

Feeding

Feed with a balanced, water-soluble liquid fertiliser diluted to half the manufacturer's recommended strength, applied once a month during spring and summer. Avoid high-nitrogen feeds that promote rapid, soft growth susceptible to pest damage. Do not feed during autumn and winter when the plant is not actively growing, as unused nutrients can accumulate and cause root damage. Flush the compost through with plain water every few months to prevent salt build-up.

Humidity and temperature

This species requires high ambient humidity, ideally between 60 and 80 percent, to remain in good health. In UK homes, where indoor air is typically dry, particularly during winter when central heating is in use, supplementary humidity is almost always necessary. Grouping plants together, placing the pot on a tray of damp pebbles, or using a room humidifier are all effective strategies; misting directly onto the fronds is less reliable and can encourage fungal spotting if water sits on the leaves. Maintain temperatures between 18 and 27 C and avoid placing the plant near cold draughts, open windows in winter, or heat sources such as radiators.

Repotting

Repot in spring when roots begin to circle the base of the pot or emerge from the drainage holes, typically every two to three years. Choose a pot only one size larger than the current one, as Crocodile Fern is somewhat tolerant of being slightly root-bound and an oversized pot increases the risk of waterlogging. Handle the rhizome gently during repotting as it is relatively delicate. Terracotta pots aid aeration but require more frequent watering; plastic pots retain moisture longer and may be preferable in drier rooms.

Pruning

Pruning requirements are minimal. Remove any brown, yellowed or damaged fronds by cutting them cleanly at the base with clean, sharp scissors or pruning snips. This tidies the plant's appearance and directs energy towards healthy new growth. Do not cut fronds that are still partially green, as they continue to photosynthesise. There is no need to cut back healthy fronds to encourage bushiness, as this fern does not branch from pruning cuts in the same way that a shrub would.

Is Crocodile Fern toxic?

Common problems

How to propagate

Division

During repotting in spring, carefully separate the rhizome into sections, each with at least one healthy growing point and a portion of roots, using a clean sharp knife. Pot each division into appropriately sized containers with fresh humus-rich compost and keep warm and humid until new growth appears.

Rhizome cuttings

Cut a section of healthy rhizome at least 5 cm long with a clean blade and pin it horizontally onto the surface of moist sphagnum moss or a fine bark mix, ensuring the underside contacts the medium. Keep in a warm, humid environment and the section should produce new fronds within several weeks, though this method can be slow and inconsistent.

Spore propagation

Collect ripe spores from the underside of mature fronds by placing a frond face-down on white paper overnight. Sow the spores thinly onto the surface of moistened, sterilised, fine compost in a covered propagator at 20 to 24 C. This is a lengthy process taking many months to produce plantlets and is rarely practical for home growers.

Where Crocodile Fern comes from

Native to Peninsular Malaysia, Borneo, Philippines, New Guinea, northern Australia.

Story and origins

The genus name Microsorum derives from the Greek words 'mikros' meaning small and 'soros' meaning heap, referring to the small clusters of spore-bearing structures (sori) found on the undersides of the fronds, which are characteristic of this genus. The species epithet musifolium combines the Latin 'Musa', the genus name for bananas and plantains, with 'folium' meaning leaf, and translates roughly as 'banana-leaved', a reference to the broad, strap-shaped fronds that bear a superficial resemblance to banana foliage. The common name Crocodile Fern is entirely descriptive, coined in the horticultural trade for the unmistakable reptilian texture of the leaf surface.

Microsorum musifolium was formally described by the German-Dutch botanist Friedrich Anton Wilhelm Miquel in the nineteenth century, during a period of intensive botanical survey of the Malayan Archipelago and surrounding regions. The species is indigenous to a broad swathe of tropical Southeast Asia including Malaysia, Indonesia and the Philippines, as well as parts of northern Queensland in Australia, where it was encountered by European naturalists during colonial-era botanical expeditions. It did not become widely cultivated as a houseplant in Europe and North America until the latter part of the twentieth century, when the cultivar 'Crocodyllus' was propagated commercially and its striking textural foliage found favour with interior designers and plant enthusiasts seeking bold, unusual specimens. It carries no particular cultural symbolism in its regions of origin and is valued purely as an ornamental foliage plant in cultivation.

Varieties to know

Microsorum musifolium 'Crocodyllus'

The most widely cultivated form in the houseplant trade, selected specifically for its particularly pronounced tessellated patterning. Plants sold under the common name 'Crocodile Fern' in garden centres are typically this cultivar.

Fun facts

• The distinctive crocodile-skin patterning on the fronds is caused by the sclereids, a type of supportive cell, and the prominently raised vein network visible through the translucent leaf surface rather than by any pigmentation.
• In its natural habitat across Malaysia, Indonesia and northern Australia, Microsorum musifolium is epiphytic, anchoring itself to tree bark with its creeping rhizome rather than growing in soil.
• The fronds can grow to over 1 metre in length in optimal outdoor conditions in the tropics, though houseplant specimens typically reach 30 to 60 cm.
• Like all ferns, Microsorum musifolium reproduces via spores rather than seeds; the spores develop in clusters called sori on the underside of mature fronds.
• The plant is closely related to the commonly kept Kangaroo Paw Fern (Microsorum diversifolium) and shares many of its cultivation requirements.

Crocodile Fern FAQ