PlantAmnesty founder Cass TrumbllCass Turnbull's latest book, Cass Turnbull's Guide To Pruning, Third Edition, was published in 2013 by Sasquatch Books and distributed by Random House.  She was also the author of The Complete Guide to Landscape Design, Renovation and Maintenance, available on our website in electronic format -- as a benefit of PlantAmnesty membership.

Cass Turnbull left the Seattle Parks Department in 1986 after 11 years to start her own landscape maintenance and consulting business.  One year later, she founded PlantAmnesty, a private nonprofit organization that now numbers nearly 1,200 members in 46 states and five countries.  PlantAmnesty's goal to "end the senseless torture and mutilation of trees and shrubs" has gained considerable local and national press as the organization strives to educate the commercial and public sectors on responsible, appropriate pruning and landscape management practices, establishing a standard of quality care for the urban ecology. Cass also founded TreePAC, an organization focused on protecting, maintaining and increasing the urban forest.

Born in Seattle in 1951, Turnbull studied for a liberal arts degree at Fairhaven College of Western Washington State University in Bellingham, Washington. She was a Washington State Certified Landscaper and a Certified Arborist--and taught horticulture at Washington State Vocational Schools. A veteran of the King County Master Gardener Program, she also studied horticulture at the University of Washington Center for Urban Horticulture and at Edmonds Community College.

Turnbull lectured widely to parks departments, school districts, community clubs, commercial landscape groups, flower and home shows, and industry seminars.  She was frequently published and interviewed on the subject of pruning reform and won four awards for her work--which included not only teaching and lecturing, but also PowerPoint Presentations, instructive pamphlets, a quarterly newsletter, information booths, a how-to book, and YouTube videos. Cass Turnbull died January 26th, 2017 while on vacation in Hawaii. She resided in Seattle with her husband, two cats, and garden.

Read some of the many memories and tributes to Cass here. Read Cass' Seattle Times obituary here. The Evergrey ( also published a fitting tribute to Cass.

One of her final efforts was No Place for Old TreesDespite research quantifying the multiple values of the urban forest, trees and green spaces are in greater danger than ever before. Find out why and how developers captured the high moral ground in Seattle. And, learn how trees can and must go hand in hand with DENSITY. No Place for Old Trees is also available on the PlantAmnesty YouTube channel.

Cass' Density Rant

Part I: No Place for Old Trees
Part II: Green Roofs and Bio Swales
Part III: Green Walls, Green Facades and Permeable Pavement
Part IV: Why We Don't Fund the Urban Forest and Green Space Programs
Part V: Common Misconceptions

How I Met Cass Turnbull from Loving Legacy Video on Vimeo.