Western Sword Fern: Polystichum Munitum Grow And Care Guide

What Are Western Sword Ferns?

Western Sword fern, scientifically known as Polystichum munitum, is a popular outdoor fern.

It is native to the tropical regions of the world and the most abundant ferns in areas like western North America, Southeast Alaska, South Dakota, Southern California, Baja California of Guadalupe Island, British Columbia, Montana, Mexico, Ireland, and Great Britain.

Related post: 23 Types Of Ferns To Grow Indoors or Outdoors in the Garden

These evergreen plants are drought tolerant and deer resistant.

what are sword ferns

The green fronds of Sword ferns can be as tall as 6 feet and grow in tight clumps spreading out from the round base.

They have a single-pinnate, and every pinna situating on it is 6-inch long, and their edges are serrated with fascinating tips.

Each frond can live for up to 2.5 years and stay connected to the plant’s rhizome.

These ferns produce light yellow spores, and the dead fronds remain attached the entire winter. The Sori occupy a vast area in two rows underneath the fronds.

A study has found that black bears in America often forage the sword fern [1].

General Information

  • Scientific name: Polystichum munitum
  • Common name: Western sword fern
  • Plant height: 6 feet long
  • Sun exposure: Full or partial shade
  • Soil moisture: Moist soil
  • Drainage: Well-draining

Polystichum Munitum – Western Sword Fern Care

Light Requirement

These native ferns can tolerate a range of sun exposures and light intensities.

Western sword fern grows best in shady areas, but they can effectively tolerate dry shade or filtered sunlight in a dense growth of Western Red cedars or Douglas firs.


Western sword fern can grow in almost all soil conditions, including dry or wet.

Before you plant them in your home garden, make sure that the soil is rich in organic matter.

They need sufficient moisture in the soil to thrive during the dry periods.

Water and Fertilizer

While planting Western Sword ferns in the garden, you should use well-draining soil and provide humus-rich content to increase moisture-holding capacity.

You should water deeply and regularly during the spring and summertime as this is their growing season.

Once these plants have adapted to your garden, water and fertilize them properly will ensure a healthy and extensive root system.

This hardy fern will not require too much observation if they can establish themselves.

Temperature and Humidity

Fern plants prefer temperatures between 65- and 75-degrees Fahrenheit. If the temperature reaches above 75-degree F, a few plants find it hard to adapt to the condition.

As a tropical fern, Western Sword fern requires higher temperatures and humidity.

It is good to place the sword ferns in the bathroom, as it is a highly humid area in the house.

If you are growing them in your garden, try to grow more plants around the sword fern. It will increase the humidity level. You can also use a humidifier to maintain humidity.

Propagation and Pruning

propagation and pruning sword fern

The young ferns and their fronds, also known as fiddleheads, usually appear during the early spring.

They come out from the underground rhizomes, unfurling themselves during the peak season. They disperse the spores via the wind [2].

You may want to grow a new fern from the mother plant in your garden. To do this, you have to carefully separate the roots using a spade or a sharp knife.

The separated section must have fronds and fresh foliage. Plant it during the first growing season, and water the planted part.

Pruning helps the plants look clean and tidy.

Sword fern doesn’t require frequent pruning as they remain evergreen for a more extended period. Sword ferns mainly propagate via their spores.

Growers need to prune the wilted fronds in the spring to keep them look green and alive.


When should I mist the Sword ferns?

If the air seems too dry, you need to mist the fern too often. Dry air indicates a lower humidity level.

Is a Sword Fern (P. Munitum) aggressive and Invasive?

This species grows very fast if provided with adequate moisture and humidity. Depending on the growing environment and climate, sword ferns are known to be invasive plants.[3]

How can I plant Sword Ferns (P. Munitum)?

It would help if you waited for spring to divide the new sword fern, its roots, and fronds from the mother.

Sword ferns are common in wooded areas, especially moist woodlands, but still, they are extremely popular garden plants. They can protect the ground from erosion.

People can easily grow this fern in the garden due to its simple requirements.

However, if you try to plant western sword fern indoors, you will have to maintain it properly by meeting their demands.


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