Western sword fern is the big evergreen fern that fills the shady floor of the lower forests around Mt. Hood. Its leathery fronds commonly reach 3 feet or more, stay green all winter and last several years. Old fronds wither but stay attached, so a mature clump often wears a brown skirt beneath the fresh green growth.
It thrives in moist, nutrient-rich soil under Douglas-fir and western hemlock, where it often dominates the ground layer. Ecologists treat a thick carpet of sword fern as a sign of a damp, fertile site. It is very tolerant of shade, though it also grows in openings, and it tends to reach its best growth in older forests.
Sword fern spreads mostly by spores rather than by creeping underground, which is why it grows as separate clumps instead of a continuous mat. Turn a frond over and you may see rows of round, brown spore dots on the underside of the leaflets, and fronds carry spores in every season. When fire passes through, the stout, woody rootstock can survive and send up new fronds as long as the soil was not heated too much. On dry, exposed sites recovery is slower.
How to identify it
A large clump of stiff, evergreen fronds, commonly 2 to 5 feet long, each divided once into narrow leaflets. Every leaflet has a small pointed lobe at its base that sticks up like the hilt of a sword, and fine, spiny teeth along its edge. Round spore dots sit in rows on the leaflet undersides, and the frond stalk is thickly covered in brown scales.
Habitat
Moist, shaded conifer and mixed forests, especially under Douglas-fir and western hemlock, from low elevations into the middle mountains. It is mainly a plant of the wetter west side of the Cascades and becomes scarce on dry, exposed sites.
Sightings in the forest
538 research-grade sightings in Mt. Hood National Forest on iNaturalist, most recently on October 27, 2026. See them on iNaturalist →