Partnering for Pathogen Free Plants: Joining Forces to Keep Plants Healthy in the City of Tacoma Plant Holding Facility

Partnerships between cities and universities can help overcome the challenges of producing healthy plants free of pests and pathogens for urban planting and restoration. In Tacoma, a partnership with researchers from Washington State University (WSU) helped the City of Tacoma implement best management practices in its plant holding facility (PHF). The PHF is a critical resource for improving open spaces, managing stormwater, and fostering community environmental stewardship throughout Tacoma and Pierce County. It supports urban forestry and natural area restoration by cultivating 8000 native plants and 1000 street trees for planting into restoration sites and neighborhood streets respectively. While many cities would benefit from similar facilities of their own, management can be challenging. For example, in fall 2021 a Phytophthora outbreak at the PHF led to the loss of hundreds of plants. Phytophthora is a genus of plant-damaging oomycetes (water molds) that thrive in wet conditions. Plant pathogens in this group spread through water and soil to cause diseases that can kill plants, possibly causing serious problems for planting stock, forests and restoration projects. Partnering with researchers from WSU was essential for collaboratively developing improved best management practices and implementing lessons learned by other small-scale nurseries. The partnership improved the function of the facility by helping address disease pathways, reduce re-infections with pot steaming, improve overall equipment hygiene, and train conservation crews.

In a nutshell, this resource offers:

• A description of the Tacoma plant holding facility.
• A partnership model for addressing nursery stock issues. 
• An approach for managing pathogens in public plant nurseries. 

How to use this resource:

• As an example of a practical academic partnership. 
• As specific actions to address pathogens, specifically Phytophthora, in plant nurseries.

Author: Elizabeth N. Matteri, Michael T. Yadrick Jr., Joseph M. Hulbert, Marriane Elliot, and Lisa M. Kenny

Date published: April 24, 2025

Point of contact: Elizabeth Matteri LMatteri@cityoftacoma.org

Citation: Matteri, Elizabeth N.; Yadrick, Michael T. Jr.; Hulbert, Joseph M.; Elliott, Marianne; and Kenny, Lisa M. (2025) "Partnering for Pathogen Free Plants: Joining Forces to Keep Plants Healthy in the City of Tacoma Plant Holding Facility," Cities and the Environment (CATE): Vol. 13: Iss. 1, Article 44. DOI: 10.15365/cate.2020.130144 

Resource is available online here.