Grow and Care for Giant Leather Fern

Grow giant leather fern in soil that stays wet. Giant leather fern is Acrostichum. Shops also say inland leather fern.

Keep the soil wet, and give it shade or sun only beside water

giant leather fern is a 6-to-12-foot evergreen fern with leathery pinnate fronds. Site it in part shade, or in full sun only where the ground stays wet beside water. [1] Hot sun on a dry bank browns the leaflet edges, and people then think the plant is dying. If the bed can dry, water weekly so the roots never sit dry. [2] It is a hedge or specimen in moist ground, not a low groundcover, and it is not drought-tolerant.

Grow it in a large pot that stays wet

A patio bowl that dries between waterings is the wrong job. If you must use a pot, use a wide, heavy one that stays wet at a pond edge.

1. Use a wide, heavy pot that will not tip when the fronds reach 6 feet or more.
2. Fill it with a heavy organic mix that stays wet, not a gritty houseplant mix.
3. Sit the pot in a tray, or at the pond edge, so the lower few inches stay in water and the crown stays above the waterline.
4. Water so the mix never dries. A small indoor bowl is the wrong size for this clump. [3]

Plant in wet ground, with the rhizome just under the surface

Plant a nursery clump in wet ground in any frost-free month. Set the rhizome just under the soil surface, at the same depth it grew in the pot, and leave about 3 to 5 feet so the clump can open to 5 to 10 feet.

1. Choose a pond edge, bog, or low wet strip. Skip a dry berm or a raised bed that dries.
2. Keep the root ball wet while you work, and handle the soil ball carefully so it does not crack apart.
3. Set the rhizome just under the surface. Backfill with the soil you removed, and water so the hole stays wet.
4. Leave about 3 to 5 feet between plants. A mature clump can spread 5 to 10 feet.
5. Mulch to hold moisture, and keep the mulch off the crown.

Split a crowded clump in warm weather

Division in warm weather is the practical start if you already have a clump. Replant at once in wet ground.

1. Lift a crowded clump with a wide spade while the soil is wet.
2. Slice sections that each have several healthy fronds and a firm piece of rhizome.
3. Replant at once, just under the surface, and keep the new plants wet until new fronds stiffen.

Cut old brown fronds at the base

Cut old brown, salt-burned, or storm-torn fronds at the base. Do not shear the whole clump hard more than once a year. [4]

1. Wait until a frond is brown, salt-burned, or broken. Green fronds still feed the rhizome.
2. Cut that frond at the base with clean loppers.
3. Leave the remaining green fronds in place.
4. After a storm, take out snapped fronds the same way.

Not florist leatherleaf — and not Boston fern

Florist leatherleaf is Rumohra, a glossy 2-to-3-foot fern sold as cut greenery, not this 6-to-12-foot wetland clump. Boston fern and macho fern are Nephrolepis house and patio ferns — see How to Grow Boston Fern. Leatherleaf mahonia is Oregon grape — see How to Grow Oregon Grape. Leatherleaf acacia is an arid tree — see How to Grow Acacia. Leatherleaf viburnum is a shrub — see How to Grow Viburnums. Golden leather fern is Acrostichum aureum, a mangrove cousin with fertile pinnae mostly at the tips; it is not a second shop card here.

Keep the soil wet, and cut brown fronds at the base so new fronds can take their place.