The Pennsylvania Horticultural Society has filled four senior leadership positions to continue driving the organization’s vision of using horticulture to advance the health and well-being of the Greater Philadelphia region. The leaders include: Patti Gregory as VP of Human Resources; David Chrystal as Director of Annual Giving; Melissa Raffel as Director of Volunteer Programs; and Tim Ifill as the Associate Director of Trees.
Each position is critical in expanding PHS’s impact in four specific areas throughout the Philadelphia region: increasing access to healthy food, creating better living environments, building deeper social connections, and growing economic opportunity.
A brief overview of each PHS leader’s role is included below.
Patti Gregory—Vice President of Human Resources
Patti Gregory was promoted to Vice President of Human Resources in May. Patti serves on PHS’s Executive team and, through her leadership, will help lead PHS to a state of improved employee engagement, providing PHS with an increased ability to develop and execute workforce strategies that support its business plan and long-term organizational direction. Her specific areas of oversight include compensation and benefits, payroll management, development of a high-performing, diverse, inclusive, equitable workplace culture (as head of the DEI and Values team), employee relations management, and talent management. Patti continues to report to the Chief Financial and Administrative Officer, Tamela Vieira.
Gregory came to PHS in 2017 as a consultant and, within a year, was brought on full-time to support PHS’s HR function. Before joining PHS, she spent 23 years in consulting in various roles, including 21 years as a Partner at Towers Perrin, a human resources consulting firm.
“Patti has elevated our human resources department to new heights and has been a key leader in embedding more diversity, equity, and inclusion initiatives into our organization,” said Vieira. “As PHS continues to adapt to the evolving needs of the horticulture and non-profit business industry, Patti will be key in finding and developing our talent to meet industry demands.”
Gregory received her B.S. in Business Administration from Drexel University and has her Professional of Human Resources certification from HRCI.
David Chrystal —Director of Annual Giving
As PHS’s Director of Annual Giving, Chrystal is responsible for leading the cultivation and stewardship of annual member and donor programs, reaching new philanthropic audiences through a newly-established impact membership model, and developing cross-departmental, donor-supported initiatives. The position reports directly to PHS Chief Development Officer Nancy Boutté Finn, and will oversee a team made up of the Director of Membership, Associate Director of Individual Giving, Manager of Annual Campaigns, and Manager of Donor Events.
Chrystal joins PHS with a deep background in fundraising and business development. He spent 14 years with the Rainforest Alliance in multiple roles including Senior Manager and Membership Manager positions. He left to join the Gobel Group, a consulting firm in healthcare philanthropy, as the Director of Business Development.
“We are excited to have someone with David’s exceptional background in fundraising and philanthropy join PHS as the Director of Annual Giving,” said Boutté Finn. “He is going to be a critical part of expanding our support base to increase our impact and advance our 2027 vision.”
Chrystal holds dual B.A. degrees from Bucknell University in Economics and Environmental Studies, along with an M.B.A. from the Stern School of Business at NYU.
Melissa Raffel, CAPM —Director of Volunteer Programs
As the Director of Volunteer Programs, Raffel is responsible for leading and implementing the strategic direction of PHS’s volunteer programs to advance the organization’s vision. Raffel will head all activities for more than 4,000 dedicated, passionate, and energetic volunteers that support year-round PHS programs and the annual Philadelphia Flower Show. Raffel will report directly to Sam Lemheney, Chief of Shows and Events, and will oversee a Volunteer Specialist, a Volunteer & Exhibit Specialist, and a Data Specialist.
Raffel has nearly 20 years of experience in the non-profit space, with more than a decade spent managing volunteer programs. Prior to PHS, Melissa worked at the Project Management Institute (PMI), a nonprofit membership association with 10,000 volunteers worldwide. At PMI, she oversaw policies and procedures related to volunteer engagement, recognition, and satisfaction, as well as training and supporting staff working directly with volunteers.
“Over the course of the year, PHS engages thousands of volunteers who are a critical part to the success of PHS programs and the Philadelphia Flower Show,” said Lemheney. “Melissa’s experience working with large volunteer groups and in volunteer leadership was the perfect formula for PHS to continue to engage volunteers with a positive experience and help drive our vision forward.”
Melissa holds a B.A. in Theater from Russell Sage College and a M.S. in Arts Administration from Drexel University.
Tim Ifill —Associate Director, Trees
As the Associate Director of Trees, Ifill is charged with promoting and ensuring successful implementation of all operations of the PHS Trees team. This position leads the development and delivery of tree education, planting, and stewardship activities in the City of Philadelphia and surrounding region, totaling more than 1,500 trees a year for both residential and commercial use. Ifill will report to Julianne Schrader Ortega, PHS Chief of Healthy Neighborhoods, and will lead a team that includes two Urban Forestry Program Managers and the TreeVitalize Watersheds Regional Manager.
Prior to PHS, Ifill served as Executive Director of Philly Fellows for 13 years, a program he co-founded that builds capacity for Philadelphia anti-poverty organizations and helps young people start careers in public service. He started his career with the U.S. Forest Service, where he served at the Inyo National Forest as the Visitor Use Assistant. Most recently, Tim served as Principal at Wild Roots, an organization which focuses on changing the way people think about their yards, gardens, and public spaces by bringing nature into communities and creating beautiful, sustainable spaces.
“Trees and increasing the tree canopy are critical to the health and well-being of local communities,” said Schrader Ortega. “Tim’s non-profit executive leadership experience, networking contacts with community-based organizations, and passion for creating positive change made him the perfect candidate to increase the overall impact of our tree program and also empower people across the Greater Philadelphia region to come together to expand our region’s tree canopy.”
Ifill received his B.A. in Linguistics from Haverford College.
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