Western Oak Fern
Gymnocarpium disjunctum
Last reviewed: August 2026
Toxicity unknown
Western Oak Fern (Gymnocarpium disjunctum) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
part shade
Water
medium
Size
6"–18" H × 8"–24" W
Bloom
N/A
Native to
CO, ID, MT, OR and 2 more states
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 437 programs across 44 states, each with a link to the provider and the date we last checked it.
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Western oak fern is a delicate, low-growing native fern that forms neat clumps of triangular, lacy fronds. It thrives in partial shade and provides soft textural contrast in woodland gardens and shaded borders. The fronds die back in winter, emerging fresh each spring.
In an HOA neighborhood
Western Oak Fern is an HOA-friendly choice. Maintenance level: low. Tidiness: 4 out of 5.
Works well in: front yard, foundation, mid zone.
- Dies back completely in winter leaving bare spots
Wildlife value
As a fern, it doesn't produce flowers for pollinators but provides habitat for small insects and spiders. The dense fronds offer shelter for ground-dwelling creatures and small wildlife.
Common questions
- How much sun does Western Oak Fern need?
- Western Oak Fern grows best in part shade conditions.
- Where is Western Oak Fern native?
- Western Oak Fern (Gymnocarpium disjunctum) is native to CO, ID, MT, OR and 2 more states, per the World Checklist of Vascular Plants (Kew).
- Is Western Oak Fern HOA-friendly?
- Western Oak Fern is generally an HOA-friendly choice in the right placement, with low maintenance.
Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Ready to grow Western Oak Fern? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Not sure where to start? Take the 2-minute yard quiz