Mary Tipping has held the position of Curator and Plant Recorder at the Scott Arboretum & Gardens at Swarthmore College in Swarthmore, Pennsylvania, since 2015, after working as the Horticulturist at the Henry Schmieder Arboretum of Delaware Valley University in Doylestown, Pennsylvania.  In her current position, she is responsiblefor curating, recording, mapping, and labeling a vast array of plant collections, which encompass over 11,500 woody plants and thousands of herbaceous plants. 

She is an ISA Certified Arborist® and the PhiladelphiaFlower Show Nomenclature Chairman.  Her plant passions include oaks, beeches, Stewartia, conifers, witch-hazels, deciduous azaleas, and ferns, just to name a few.

Ethan Kauffman is the first director of Stoneleigh: anatural garden, where he has led the transition from a private estate to a public garden over the last 8 years.

He developed his love of the natural world by exploring the Susquehanna River Hills in Southeastern Pennsylvania. He cultivated his horticultural perspective over two decades of gardening in the Deep South, including as director of Moore Farms Botanical Garden, where he also led the transition from a private pleasure garden to a public botanical garden.  Drawing on influences from both regions, he enjoys creating a garden experience at Stoneleigh that inspires others togarden for beauty, biodiversity, and the health of our planet.   

Trinity Pierce is the Chicago Region Trees Initiative senior stewardship manager at The Morton Arboretum. She collaborates with community organizations and members toincrease awareness and foster action through plantings and ongoing care in order to grow a more diverse, more abundant, and more equitably distributed urban forest. A Certified Arborist, she holds a Master of LandscapeArchitecture from the University of Michigan with a background in history, ecological restoration, and urban green space reconciliation.

Katherine Mills, General Manager for Munstead Wood, is anexperienced heritage professional with 14 years in the National Trust. Having run some of the charity’s most significant and popular properties, including Nymans, West Sussex, and Polesden Lacey, Surrey, UK; Katherine was responsible for the final purchase and acquisition of Munstead Wood in April 2023. 

Since acquiring the property, Katherine has recruited a team of individuals to care for the house and garden, as well as develop plans for restoring Gertrude Jekyll’s home, providing future access, and securing its long-term future.

Jehane Samaha is the National Urban Nursery Specialist with the US Forest Service. She develops trainings and networking for both urban foresters and nursery growers to improve tree stock quality, enhance connectivity in the urban nursery pipeline, and promotes climate-adaptive genetics for urban trees.

Jehane is based in Philadelphia, serves on the board of UC (University City) Green, and previously worked at PHS (Pennsylvania Horticultural Society) and the Morris Arboretum.

She is an ISA Certified Municipal Arborist® through the International Society of Arboriculture, and completed a master’s thesis at UBS (University of British Columbia) on street tree species selection.

Della Fetzer is a biologist and entrepreneur. Her company, Rebel Cultures, partners with foresters, farmers, conservationists, greenhouses, and universities to develop low-cost and biodiversity-conscious propagation solutions for seed-scarce plants, and plants that can't be efficiently propagated from seed by using new approaches to tissue culture.

Jamie Biddle is the founding partner and CEO of VerdisInvestment Management, a single-family office. He sets the strategic direction of the firm, and overseas investment activities, operations, and finance. Jamie is behind portfolio construction, manager sourcing and selection, due diligence,and risk management. He is an active member of the Investment Committee.

Jamie brings more than two decades of investing and operating experience, across asset classes and industries. Prior to forming Verdis Investment Management in 2004, Jamie was President and CEO of Orcom Solutions. Orcom was an outsourced customer care and billing service for electric, gas and water utilities across North America. The company was originally purchased by a group of private equity firms (including the Blackstone Group and Thomas H. Lee Partners) led by Jamie and was sold to Alliance Data Systems (NYSE:ADS) in December 2003. Jamie began his career as a VC at EnerTech Capital Partners, funding technologies in energy and power.

He earned his Master’s in Business Administration from theWharton School of the University of Pennsylvania and a bachelor’s degree from the University of Pennsylvania. Jamie is the Chairman and President of Andalusia Historic House, Gardens, and Arboretum and Vice-Chair of the Board ofTrustees and Chair of the Museum Committee of the Pennsylvania Academy of the Fine Arts.

Linda Langelo is a Colorado State University Extension Horticulture Specialist and host of the Relentless Gardener Podcast. The five counties under her care are in Northeast Colorado, where she assists homeowners and professionals with horticultural issues. She created a Facebook page titled, Garden the Plains to reach a broader audience with the help of Master Gardeners. The Master Gardener Program in the Golden Plains Area covers demonstration gardens, school and library programs, community gardens, and more.

During her 40 years in horticulture, she has worked in both private and public horticultural institutions. As Assistant Director of Horticulture at Salisbury State University, she helped implement an arboretum campus-wide that is still going strong today. Linda went on to be the Director at Adkins Arboretum early in its development, increasing its exposure to the local and surrounding communities. The arboretum also became a member of the American Public Garden Association under her tenure.

In July 2021, she was awarded the Lois Woodward Paul Memorial Award for her career achievements from Longwood Gardens Alumni Association as a fellow alumnus of the Longwood's Horticulture Program.

Linda is a member of Garden Communicators International,the American Public Gardens Association, a regular contributor to MarthaStewart.com, and Canada's Local Gardener. She has worked on diverse landscapes from public to private gardens including resorts and arboreta for 40years. Linda worked from New York to New Mexico, before arriving in the Golden Plains area of Colorado where she has spent the last 19 years of her career.

Her Relentless Gardener column has received a Laurel Award from Garden Communicators International.

Jay Worth started working in the Green Industry in college to earn money between semesters. He started mowing lawns for a landscaping company and then moved to a full-service landscaper. While attending University in Florida, he alsoworked on a palm tree farm and fell in love with the trees.

 During the Great Recession in 2009, he was recruited to sell lawn care door-to-door. Having no other job options, he took the offer. This was the beginning of his full-time career in the Green Industry.

After several years he took a break to work in media sales before returning to the Green Industry. Eventually, he landed at a full-service landscaping company doing Inside Sales for their lawn care and pest control programs. Jay gotpromoted to run all the marketing and grew his single Inside Sales position into an entire team of people.
While working there, he spent every chance he got outside with the Tree Care team. He met them on job sites, talked to them at the shop, and even spent time in the field during ISA Arbor Day of Service events.

He eventually connected with SingleOps, a software he’d used while working at one of the landscaping companies. He found it to be the best option for Tree Care and full-service Landscaping companies. So, when they wanted someone to create resources for business owners, he found it was an easy product to get behind.
Jay is passionate about best practices for healthy plants, sustainability, and being thoughtful stewards of the environment. He is also especially keen to help business owners and managers become more effective and efficient in their business practices. Jay sees no reason those two cannot coexist.

Kevin Zuidervliet is owner and grower at Octoraro Native Plant Nursery, in Kirkwood, Pennsylvania. His diverse professional experience and passion for horticulture began while traveling and working on organic farms in Australia and New Zealand. He leveraged his skills in an AmeriCorps VISTA position managing a community garden. Kevin continued to hone his plant knowledge at Shaffer Landscapes, in

Kevin has come full circle at Octoraro, where he is using his skill sets to create regional plant palettes for designers, ecologists, and others in the industry to maintain, enhance, and recreate lost habitats in the region.