The Western Sword Fern (Polystichum Munitum) Care Guide

The Western Sword Fern, otherwise known as the Polystichum Munitum or Sword Fern, Giant Holly Fern, Aspidium munitum, is a somewhat well known fern plant native to the Pacific Northwest, and the Rocky Mountains of the United States.

Best known for its low maintenance and moderate growth, this fern will likely liven up your house (or garden) with its green colored leaves. But, only if you learn how to take proper care of it for it to thrive.

Fortunately, this is exactly what we’ll cover in this Western Sword Fern Care Guide. So let’s dive in.

In order to take proper care of your Western Sword Fern you’ll need to keep in mind the following guidelines:

  • Water: The Western Sword Fern grows best with regular watering to keep the soil moist during the dry season. Reduce watering once the plant is established.
  • Light: Keep your Polystichum Munitum in an environment where it can receive full shade to partial sun on a daily basis. 
  • Soil: Make sure to keep the Western Sword Fern in soil with moist but well-draining properties, so ideally, one that is made of clay, loam, chalk, and sand.

And as with many other plants, these are the only three care factors you need to remember to make sure your Western Sword Fern is, for the most part, healthy and well to survive.

Polystichum munitum leaves

Scientific / Botanical Aspects

In botanical terms, the Western Sword Fern belongs to the Polypodiaceae family, the genus Polystichum and the species Munitum, hence its scientific (or botanical) name Polystichum Munitum (pol-ISS-tih-kum MEW-nih-tum).

As with other Polystichum’s, the Western Sword Fern is an evergreen plant, which means it will be present year round in your garden.

Growing Region

The Western Sword Fern is a plant native to the W. North America. This is why the Polystichum Munitum is used to growing in specific regions such as the states in Pacific Northwest, and the Rocky Mountains of the United States.

Knowing your plant’s native region is very useful, as it can give you tips on which environment is best for your Western Sword Fern. If you keep it in mind, you can try to replicate these conditions at home, and you’ll likely end with a healthier plant.

With this in mind, the Polystichum Munitum will be most used to the heat zones in the 1 – 8 region, and in climate zones that range between 2, 2A, 2B, 3, 3A, 3B, 4, 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, A3.

Growth and Size


In terms of size and growth, the Western Sword Fern is a relatively moderate grower, which makes things somewhat easy for any plant enthusiast.


But, what size of Western Sword Fern are we talking about? What can you expect in terms of height, spread and spacing? Let’s dig in…

The Polystichum Munitum can grow up to 2′ – 4′ (60cm – 120cm) in 2′ – 4′ (60cm – 120cm) and 2′ – 4′ (60cm – 120cm) in 2′ – 4′ (60cm – 120cm). 

These dimensions make the Western Sword Fern a relatively medium fern compared to others, so it’s best to keep this fact in mind since it will affect where you want to keep yours at home.

Also, expect it to grow in a wonderful spreading shape, which is something worthwhile to remember when making your garden landscape plans.

This is why experts recommend keeping an area of approximately 24″ – 48″ (60cm – 120cm) free so the Western Sword Fern can spread to its best extent.


In terms of watering, the Western Sword Fern is a fairly complicated plant to take care of.

This is mostly because it has a not so straightforward watering schedule and somewhat regular watering needs.

Specifically, most experts agree that the Polystichum Munitum grows best with regular watering to keep the soil moist during the dry season. Reduce watering once the plant is established.

Which is why it is considered a plant with relatively average needs in terms of water. 

Polystichum munitum care


As a rule of thumb, you should remember to keep your Western Sword Fern in soil with moist but well-draining characteristics, as these will guarantee the right conditions for your plant to grow and thrive. 

However, in our experience, the best solution to knowing the right amount of water for your Western Sword Fern is with the ‘thumb’ technique. Basically, you insert your finger into the soil, and based if you feel the soil moist or dry, you determine if it needs any water, which is the most appropriate way to go about watering your leafy friend.

Soil Mix

The Western Sword Fern’s ideal soil potting mix is made out of clay, loam, chalk, and sand.

In addition to this, expert gardeners recommend having preferably alkaline, acid or neutral soil.

Light and Exposure

In terms of light & exposure, the Western Sword Fern requires full shade to partial sun in order for it to thrive under the right conditions. 

Most experts agree that this fern will do well as long as you keep it in partial sun to shade, and it will be able to grow properly.

Specifically, we recommend that you place your Polystichum Munitum in little to partial shade (only 2-6 hours of direct sunlight a day), to full and direct sun (more 6 hours of direct sunlight per day).


Being an evergreen plant, the Western Sword Fern will be present year round in your garden.

But, you can expect it to have its ‘prime-time’ during the spring (early, mid, late), the summer (early, mid, late), the fall, and during the winter.


The leaves from the Western Sword Fern have a beautiful green color during most of the year.

In particular, they have a compound (pinnately, bipinnately, palmately) and fronds arrangement in its leaves.

Polystichum munitum and bees


How should you then organize your garden to include your new Western Sword Fern? Here are some recommendations by expert gardeners.

Most Polystichum Munitum owners agree that this fern will look great in most rustic, asian/zen and tropical gardens of all types. 

Other owners consider that they complement well most gardens of prairie and meadow, informal and cottage, and in traditional garden styles. 

In particular, the Western Sword Fern’s best location within your garden is in beds and borders, and in underplanting roses and shrubs, others use it for landscaping in a erosion control, poolside, border, mass planting, or a woodland garden.

Companion Plants

Western Sword Fern’s do well with some other plants beside it. One good companion plant is the Heuchera, which will pair up nicely with your leafy friend.

Others consider that a nice Aquilegia will work well too, so choose whichever you find works best for you!


And we’ve come to an end. Fortunately, that’s everything you need to know about your Western Sword Fern to keep it safe and sound in your garden or home. Enjoy planting!

Sebastian Moncada

I’m also a plant enthusiast and researcher. I’ve been privileged to have lived my whole life around the wilderness of Colombia and I’m happy to share everything I learn along the way. “Adopt the pace of nature. Her secret is patience” – Emerson.

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