Propagating Java Fern 'Sao Paulo' (Microsorum pteropus 'Sao Paulo')

How to multiply the narrow-leaved Java Fern 'Sao Paulo' by rhizome division and adventitious plantlets, then tie or glue the pieces to hardscape while keeping the rhizome exposed.

Overview

Java fern (Microsorum pteropus, also classified as Leptochilus pteropus) is an aquatic to semi-aquatic fern that naturally grows attached to riparian roots and rocks rather than in the substrate. It is highly variable, with named varieties differing in leaf size and shape; 'Sao Paulo' is a collector's selection with very narrow, ribbon-like leaves and reddish young growth. As an epiphyte it has a rhizome from which roots develop, and it propagates like the rest of the species.

Java fern is one of the most popular hobby plants thanks to its ease of care, so even this prized narrow-leaf form is straightforward to multiply once you know the rhizome rules.

Propagation Method (Rhizome Division & Plantlets)

Two asexual routes work. Rhizome division means cutting the horizontal rhizome into sections, each with roots and a few leaves. Adventitious plantlets form readily from the leaf tips and margins; these daughter ferns develop their own roots and can establish on nearby objects before the mother leaf deteriorates — and if a parent leaf fails, the small fern can float off to start anew.

Step-by-Step

1. Detach the mother plant from its wood or rock and rinse off debris.
2. For division: cut the rhizome into sections with clean scissors, keeping roots and a few narrow leaves on each.
3. For plantlets: separate daughter ferns from the leaf tips and margins once they have their own roots.
4. Tie each piece to driftwood or rock with thread, or fix the roots with a small line of super glue gel, pressing for about 30 seconds until set.
5. Keep the rhizome fully exposed on top of the hardscape and return it to the tank.

Conditions for Healthy Growth

Java fern grows well in tap water under dim or bright light, with or without gravel, and needs no CO2. It is slow-growing and snail resistant, and even grows better with higher fish loads. Stable water lets the narrow-leaved 'Sao Paulo' develop its characteristic reddish young fronds without stress.

Maintenance

Once roots wrap the hardscape the attachment is permanent and any thread can be removed. Trim away old or melting leaves; healthy plantlets that have rooted can be left in place or moved to expand the display.

Common Challenges

Burying the rhizome is the classic fatal error and causes rot. Slow establishment is normal, so resist disturbing fresh divisions. Separating plantlets before they have roots is the other common pitfall — wait until each has its own roots so it survives independently.