Acrostichum spp.

leather fern

Pteridaceae Pantropical wetlands

Deer Resistant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterHigh

HardinessZones 10–12

Overview

Acrostichum spp. is a genus of large, coarse ferns in the family Pteridaceae, with about three species growing in tropical and subtropical wetlands worldwide. The stout, erect fronds rise 1–4 m (3–13 ft) from a thick, creeping rhizome and are once-divided into many leathery, strap-shaped leaflets 15–40 cm (6–16 in) long. New fronds are often bronze or reddish before turning deep green. The fertile leaflets toward the frond tip are covered on the underside with dense brown spore-bearing tissue, giving the genus its leather-fern name. Plants form large clumps and spread slowly by rhizome into dense stands. Acrostichum spp. grows in full sun to part shade in permanently wet, muddy, often brackish ground, and is among the ferns able to grow in mangroves, salt marsh, and tidal swamp. It tolerates salt, flooding, and full tropical sun but needs constant moisture and frost-free warmth, dying back where the ground dries or freezes. The wind-dispersed spores colonise disturbed wetlands quickly, and the coarse clumps can crowd out other vegetation. Fronds are leathery and persist year-round in frost-free climates.

Native Range

Acrostichum spp. is pantropical, with species in the wetlands of the Americas, Africa, Asia, Australia, and the Pacific. The ferns grow in mangroves, brackish and freshwater swamps, tidal flats, and ditches, mostly at or near sea level in frost-free regions.

Suggested Uses

Planted at pond and lake margins, in bog and rain gardens, and in brackish and coastal wetland plantings in frost-free climates. Grown as a bold foliage clump in large containers kept constantly wet. Used in wetland restoration within its native range.

How to Identify

Recognised by tall, erect, leathery fronds once-divided into broad strap-shaped leaflets, rising in clumps from wet, muddy ground. Fertile leaflets near the frond tip are coated underneath with rusty-brown spore tissue, while new fronds flush bronze or red. The wetland, often brackish habitat sets it apart from most other large ferns.

Appearance

Size & Dimensions

Height3' - 13'

Width/Spread3' - 8'

Reaches mature size in approximately 4 years

Colors

Foliage Colors

green

bronze

Fall Foliage Colors

no change

Bloom Information

Ferns reproduce by spores rather than flowers, so Acrostichum spp. has no bloom period. Spores form on the undersides of the upper leaflets through the warm season and are released to the wind and water. New fronds appear year-round in warm, wet conditions.

Detailed Descriptions

Foliage Description

deep green, bronze when young

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

clay loam silt

Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

tender

Time to Maturity

2-4 years to full frond size

Care & Maintenance

Care Guide

Grow Acrostichum spp. in full sun to part shade in permanently wet, mucky soil at a pond edge, bog, or shallow water. It tolerates brackish and saline conditions, flooding, and heavy clay but needs constant moisture and frost-free warmth. A soil pH from about 5.5 to 7.5 suits it. The fronds brown and die where the ground dries out or temperatures drop near freezing. Plants spread by rhizome into large clumps and need room or division to stay in bounds. Little feeding is needed in fertile wetland mud.

Pruning

Acrostichum spp. needs no routine pruning. Cut old, browned, or storm-damaged fronds back to the base at any time to make way for new growth. Dividing the rhizome in warm weather controls clump size and starts new plants.