Multiagency Collaboration Strengthens Applied Research and Mitigation of Phytophthora ramorum at a Botanical Garden in Washington State

Phytophthora species pose significant challenges to public gardens, but collaboration can help contaminated gardens minimize their impacts and remain open to the public. Phytophthora ramorum was detected at the Bloedel Reserve-a botanical garden in Washington State-in 2015 but has not been recovered from surveys of plant material since 2016 following coordinated regulatory responses, research activities, and adaptative management decisions. Here we summarize efforts that were made to reduce the impact of P. ramorum on the Bloedel Reserve and limit the spread of this pathogen to nearby landscapes. Regulatory responses included detection and removal of positive plants, soil steaming, and the development of best management practices in the Reserve. Measures to adapt management in the garden included supporting applied research, removal of host plants, fungicide sprays, trail maintenance, and signage. The garden also featured P. ramorum in their education and outreach programs and used this as an opportunity to teach the public about invasive species.