Western Sword Fern
Polystichum munitum
Care
part shade, full shade
moderate
moist, humus-rich, well-drained; acidic
2–4ft tall , 2–4ft wide
Evergreen
Resistant
Friendly
Pacific Coast from Alaska to Southern California
Non-flowering; reproduces by spores
Backbone of the shade garden; extremely reliable; nearly indestructible
Care Guide
Planting
Plant your Western Sword Fern in partial to full shade - it's very forgiving about light as long as it's not in direct sun. Choose a spot with moist, humus-rich, well-drained soil; the plant prefers slightly acidic soil but tolerates clay as long as moisture stays consistent. Space plants 3-5 feet apart since they'll eventually spread 5 feet wide. Fall through early spring is ideal for planting in the Bay Area.
After Planting
Water weekly with a deep soaking for the first summer to establish a strong root system. Once established (typically by year two), you can cut back to watering just twice a month in summer, though the plant performs best with at least weekly deep watering year-round. Don't remove the old, withered fronds - they'll naturally stay attached to the base and eventually drop off on their own. The #1 mistake is letting the soil dry out; Western Sword Fern needs consistent moisture even once established, so set a weekly watering reminder rather than waiting for the plant to look droopy.
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Endangered & Threatened Species Supported
Listed under ESA in 1967; California's only native frog species that is state-endangered
Wildlife Supported
Amphibians
Critical refuge under fern fronds in moist forest floor microhabitat
Uses dense sword fern patches as shelter in riparian understory
Birds
Uses dense fern clumps for shelter and foraging cover year-round
Uses fern fronds for nest lining material during spring nesting
Arachnids
Pathogen associated with fern rhizosphere in moist conditions
Fungal associate in moist understory where fern dominates
Insects
Larval host plant for caterpillar feeding on fern fronds
Specialist beetle feeding on sword fern foliage
Specialist herbivore feeding on frond sap throughout year
Uses fern fronds for shelter and overwintering
Mammals
Lines nest cavities with fern fronds; uses understory for foraging habitat