Imbricate Sword Fern Polystichum munitum

The sword fern is a broadleaf evergreen or semi-evergreen that has large, arching, dark green, erect fronds that are born from a crown of scaly rhizomes. The plant grows to a height of 3 to 4 feet tall and 2 to 4 feet wide. They may be in clumps of 75 to 100 fronds. The fronds are pinnately compound with alternate, pointed, sharp-toothed leaflets. Each leaflet is sword-like and has a small lobe that points forward at the base, like a saber.  There are sori or spore cases that are yellowish and arranged in rows on the undersides of the fronds.  In the early spring, young fronds or fiddleheads appear and begin to unroll. Each fern can grow to a length of 4 to 6 feet and survive for several years. A fern from the Pacific coast, it has earned the Royal Horticultural Society's Award of Garden Merit.

Sword fern is native to western North America from Alaska to Mexico. It is common in moist coniferous forests in the southern coastal regions of British Columbia. It is mostly a coastal species, but it is found inland in areas such as Idaho, Montana, and South Dakota. The genus name, Polystichum, is derived from two words, poly, meaning many, and stichos, meaning rows. This references the row of spores that occur on the undersides of the fronds. The epithet name, munitum, means "armed with teeth." and references the fronds. 

The sword fern prefers partial to full shade, moist, well-drained soils in humid conditions, It adapts to various soils but prefers acidic to slightly acidic conditions. The delicate fronds will burn if exposed to full sun. In the fall when the fronds begin to die off for the winter, they should not be removed. These fronds will protect the new growth that will occur in the spring. The sword fern is propagated by spores and rhizomes. Division should be done in the early spring. The rhizomes will survive through the winter when planted in the ground, but container plants should be moved indoors. It is also important to protect the crowns from excessive winter wetness. 

Sword fern maybe sometimes confused with deer fern. The sword fern has a small stem attached to each leaflet; whereas the deer fern's leaflets are attached to the stipe along their entire margin and their margins are not toothed. 

The sword fern could be considered for a shade garden, cottage garden, or woodland garden. It may also be used as a container or houseplant.

Seasons of Interest: 

Foliage:  Year-round in warmer climates

Quick ID Hints:

• evergreen, up to 3 to 4 feet tall and 2 to 4 feet wide, clumps of up to 75 to 100 fronds
• erect, arching fronds, pinnately compound, lance-shaped
• fronds have many leaflets that are simple, alternate, finely serrated 
• clusters of yellowish spores on the undersides of the leaflets
• young fronds or fiddleheads appear in the spring and slowly unroll

Insects, Diseases, and Other Plant Problems:  Sword ferns are generally resistant to most insects and diseases. Monitor for aphids, mealybugs, fern mites, and nematodes. Browning of the tips of the leaves usually indicates a lack of water and humidity. Yellow and wilting leaves are usually the result of overwatering.

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University

More information on Polystichum.