Sword Fern Dieback

Study

The dieback of western sword fern has been observed in distinct locations around the Puget Sound. The oldest known location is Seward Park in Seattle.

Seattle Parks and Recreation, Friends of Seward Park, and many community scientists continue to investigate and track the issue. Observations of swordfern dieback have been shared on iNaturalist.

In 2024, our program visited 15 sites selected from the observations shared on iNaturalist. Soil and fine roots were collected from beneath healthy, unhealthy, and dead sword ferns at these sites.

Approach

Soil and fine roots were baited for Oomycetes (see photos below) to explore relationships with root disease causing microbes such as Phytophthora species.

Participate

Anyone can contribute to the research by collecting and submitting soil samples to our program. Contact us if you are interested in participating.