Sword fern (Polystichum munitum) adds instant lushness to shade gardens. It is perfect for a shaded backyard, north-facing courtyard, or shady patio. Sword fern fronds stand through winter with a few fading or dying back. In spring, keep an eye out for the delightful fiddleheads to pop up and unfurl as the days warm. This large, sculptural perennial is an evergreen with a big garden presence in USDA Zones 5–9.

Where to Plant Sword Fern

Sword fern grows best in shade. It will thrive in part shade—4 to 6 hours of bright light a day—or full shade—just 2 to 4 hours of bright light. Grow this large perennial under the dense shade of conifers or deciduous trees. It is well-suited for growing in the low light of the north or east side of a building. Sword fern thrives in moist, well-drained soil that is rich in organic matter. It will tolerate slow-draining clay for short periods but will not survive in boggy sites.

It is native to North America and thrives in moist, shaded landscapes. Sword fern is particularly at home in the humid coniferous regions of the Pacific Northwest.

Sword fern can also be grown as a container plant. Grow the potted plant on a shaded porch or patio in the summer. Move it indoors to a warm, humid spot in winter. It will likely drop several leaflets and a few fronds, but it will regrow quickly when you move it outside in spring.

How and When to Plant Sword Fern

 Plant sword fern in spring or early summer. Choose the planting location carefully, ensuring this large perennial has plenty of space to expand. Its massive fronds can grow 4 to 6 feet long. In moist, humus-rich soil, the plant can easily reach 7 feet or more across, but in most home landscapes, it grows 2 to 4 feet wide.

Dig a planting hole slightly wider than the plant’s root ball and just as deep. Plant sword fern so that the top of the root ball is level with the surrounding grade. Backfill with native soil, and water the newly planted fern. Continue watering weekly, keeping the soil moist but not waterlogged until the plant establishes a robust root system, usually within a few weeks. Continue watering as needed to give the plant about an inch of moisture a week.

Sword Fern Care Tips

Light

Sword fern grows best in shade. It thrives with only two to four hours of bright light a day. It can tolerate up to six hours of bright light. Plant sword fern in the dense shade of coniferous trees or deeply shaded nooks where other plants struggle to survive.

Soil and Water

Grow sword fern in well-drained soil that is rich in organic matter. In the wild, it grows in the humus-rich floor of a coniferous forest. Avoid wet or boggy soils and soil with a high clay content. Slow-draining soil is not a good fit for sword fern.

Regular moisture is critical for lush growth. Sword fern grows best with about an inch of weekly rainfall or supplemental water. This tough plant will grow in an arid environment after it establishes a strong root system, but the plants will be compact.

Temperature and Humidity

Sword fern grows well in a wide range of temperatures. Expect it to produce its dark green, evergreen fronds everywhere from the coldest parts of Zone 5 to the temperate-bordering-on-tropical parts of Zone 9. Be sure to leave faded and decaying fronds on the plant over winter; these massive leaves insulate the crown, which is especially important in cold regions.

High humidity is ideal for sword fern, which thrives in moist, humid environments. It can grow in arid regions, but its form is more compact there.

Fertilizer

In its native environment, sword fern grows in nutrient-rich soil commonly found on the forest floor. Mimic that thick humus layer by topdressing sword fern’s root zone with a 1-inch layer of compost each spring. If the local soil is sandy or lean, fertilize sword fern with an all-purpose fertilizer annually in spring, following the product instructions, and topdress with compost.

Pruning

Cut back old, faded fronds when new growth begins in spring. Resist cutting back faded fronds in fall; the old fronds will help insulate the crown through winter, making way for strong growth in spring.

Potting and Repotting Sword Fern

Sword fern can be grown as a container plant outdoors or as a large houseplant. Use a well-draining container filled with garden soil rich in organic matter or with good-quality potting soil.

When growing sword fern indoors, position it in a brightly lit room near a north- or east-facing window. Water a sword fern growing as a houseplant as needed to maintain moist, but not wet, soil. After a year, you can repot to a larger container with fresh soil, but the plant may soon become too large for most homes.

Pests and Problems

Sword fern is generally pest-free and easy to grow. Wet, boggy soil is its biggest enemy. Avoid slow growth and plant death by growing it in loose, well-drained soil.

How to Propagate Sword Fern

The easiest way to propagate sword fern is by dividing established plants. Dig up the entire clump and cut the crown into three or four pieces using a sharp spade. Each section needs ample roots and foliage. Plant the divisions immediately in places where they have space to expand.

Sword Fern Companion Plants

The best companion plants for sword fern are those that enjoy the same moist, shady locations.

Coral Bells

The gracefully rounded leaves of coral bells provide a pleasing contrast to the many-leaved fronds of sword fern. Growing in moist, shaded locations, coral bells are available in a variety of leaf colors—from chartreuse to burgundy—and a wide range of sizes. Some plants grow just 1 foot wide while others expand to as much as 3 feet wide. Plant three or more coral bells together for a drift of color and texture. Zones 3–9.

Hosta

Hostas are some of the easiest shade plants to grow. This hardy perennial is available in hundreds of varieties varying in size from 6 inches wide to more than 4 feet wide. Variegated leaves in white, green, and yellow add more options. Zones 3–9.

Lungwort

Pleasing speckled leaves combined with bright purple, white, or pink spring flowers make lungwort a hardworking perennial. Lungwort grows well in shade and part shade and is well-suited to a variety of soils. ‘Benediction’ has bright purple flowers, and ‘Opal’ (shown here) has clear white flowers. Zones 2–8.