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, with the most abundant ferns in areas like western North America, Southeast Alaska, South Dakota, Southern California, Baja California, Guadalupe Island, British Columbia, Montana, Mexico, Ireland, and Great Britain.

These evergreen plants are drought-tolerant and deer-resistant.

Quick Facts

  • 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

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

what are sword fernsPin

They have a single pinnate, and every pinna situating on it is 6 inches 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].

Western Sword Fern Plant Care

The western sword fern, or Polystichum munitum, is a dramatic evergreen perennial plant that can be used to add texture and color to any landscape.

With the right care, this plant can grow well both indoors and outdoors and will have lush leaves for years.

Even though Polystichum munitum is easy to take care of, it is important to know how much light, water, and fertilizer it needs.

This tough fern grows best in bright, indirect sunlight, but it can also grow in shade.

It does best when it gets watered often, but it doesn’t like getting too much water.

The soil of your fern needs to dry out between watering sessions for its health.


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

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


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 dry periods.


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 summer, as this is their growing season.


Once these sword fern plants have gotten used to your garden, giving them enough water and fertilizer will help them grow a strong root system.

This hardy fern will not require too much observation if it can establish itself.

Temperature and Humidity

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

As a tropical fern, the 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 fernPin

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 looking green and alive.


When should I mist the Sword ferns?

When the air appears to be dry, mist sword ferns. However, do not mist the fern too often. Try to mist your plants daily or every other day to help their fronds retain more moisture. If you can’t mist your fern regularly, don’t worry, as they can survive in drier climates; they just thrive in a moister environment.

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

Sword ferns grow very fast and aggressively when they get to grow in a humid environment. They are known to be invasive plants. Sword ferns aggressively spread throughout the landscape. [3]

How can I Spread or Propagate Sword Ferns?

Propagate sword ferns by dividing them. Wait till Spring during their growing season. First, divide the sword fern by its roots and split the rhizomes. Alternatively, they reproduce themselves by spreading their spores through the air.

Other Ferns to Consider

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

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

If sword ferns are not your cup of tea, try these other popular ferns in your garden.

  • Platycerium bifurcatum: Most known as a staghorn fern or elkhorn fern due to its antler-like frowns, these plants will add an exotic look to your yard or garden. The staghorn fern grows best in warm, humid places, so it is a good choice for people who live in a tropical climate. However, it can also handle some cold weather, as long as it is protected from frost.
  • Asparagus Densiflorus: The foxtail fern (alternatively known as the emerald fern) is an easy plant to grow as it can be planted in either full sun or even light shade. With its cascading shape and bright green leaves, this evergreen plant adds texture and beauty to your yard. The feathery fronds, which look like a fox’s tail, are a great way to give your yard some great curb appeal.
  • Matteuccia struthiopteris: Commonly known as ostrich ferns or shuttlecock ferns due to their resemblance to miniature ostrich heads. They are a beautiful addition to any garden or landscape and grow up to 6–8 feet tall. During the summer, their fronds are bright green, but in the winter, they turn a golden brown color. You can grow ostrich ferns in landscaping, borders, groundcovers, walkway edges, or even in rock gardens.


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