Holden's Instructors
Holden Staff Instructors
David Burke, PhD, holds a bachelor's degree in environmental science from Rutgers University, a master's degree biology from East Stroudsburg University and a doctorate in biology, with concentration in ecology and evolution, from Rutgers University. Burke is a plant biologist whose research focuses on the interactions between plant roots and soil organisms with a particular emphasis on mycorrhizal ecology. He is the chairman of the Research Department at The Holden Arboretum and has an adjunct position in the Department of Biology at Case Western Reserve University.
Toby Davidson, horticulture supervisor for the Display Gardens, earned his associate's degree in forestry from Hocking College. He spent the first eight of his 12 years at Holden caring for the trees in the outer collections. He enjoys pruning trees and designing garden spaces.
Julie Dougherty, the assistant manager of guest relations, is a certified interpretive guide from the National Association for Interpreters. She earned her bachelor's degree from Cleveland State University, her master's degree in sports psychology from West Virginia University and her master's in education administration from Ursuline College. She taught outdoor education at Hiram House Camp for 10 years, physical education at St. Vitus for 12 years and served as principal at St. Louis Elementary for seven years.
Viki Ferreniea, lead horticulturist at Holden, was formerly director of horticulture for the New England Wildflower Society. Ferreniea, a graduate of Swanley Horticultural College in Kent, England, received the national diploma in horticulture from the Royal Horticulture Society. She trained at the Royal Botanical Gardens at Kew, England. She is the creator of the North American wildflower garden at Longwood Gardens near Philadelphia, Pa., and has lectured and taught about wildflowers all over the country. Ferreniea is the author of Wildflowers in Your Garden, published in 1993.
Roger Gettig, director of horticulture and conservation. Gettig began his career at Holden in 1988 as a native plant intern before becoming full-time staff as natural areas foreman. He left Holden to attend the University of Wisconsin, where he majored in ecological restoration while earning his Master's degree in landscape architecture. He returned to Holden in 1996 as landscape consultant and then assumed the role of land conservation manager.
Lori Gogolin earned an associate's degree in horticulture from Kent State University in 1998. She is a horticulturist at The Holden Arboretum and is responsible for the Arlene and Arthur S. Holden Jr. Butterfly Garden.
Sharon Graper, manager of formal education, began her relationship with Holden in 1981 as a student at Hawken High School, working on her senior project in the Myrtle S. Holden Wildflower Garden. She came back as an intern in 1984 and as a summer employee teaching children’s classes in 1991. Since 1994, she has managed school and youth programming at Holden. She earned her undergraduate degree in environmental science from the University of Virginia and her master’s degree in science education from the University of Delaware.
Clement W. Hamilton, president and CEO. Hamilton grew up in Wisconsin and Ohio, where he developed his three primary passions for nature, baseball and music. He earned a bachelor's degree in geology at Harvard, and a doctorate in ecology and evolutionary biology at Washington University and the Missouri Botanical Garden. He has conducted botanical research and fieldwork in Thailand, Panama and Chile, as well as the United States. He was assistant and associate professor in the Center for Urban Horticulture at the University of Washington in 1985-99, directing the center in 1992-99; executive director of Rancho Santa Ana Botanic Garden in Claremont, Calif., in 1999-2004; and vice president for arboretum programs and director of research at the Morton Arboretum in Lisle, Ill., in 2004-08. In the spring of 2008, Hamilton became president and CEO of The Holden Arboretum, where he seeks to maximize Holden's contribution toward creating a more livable, diverse and ecologically sustainable world by promoting the planting and conservation of trees and forests.
Ethan Johnson, plant records curator, earned his associate's degree from Paul Smith’s College, N.Y., in forestry and his bachelor's degree in environmental horticulture from the University of Connecticut. He has been Holden’s plant records curator since 1989. As curator he documents the history, growth, phenology, and condition of cultivated plants in the living collection as well as produces plant accession, labels and collection maps.
Stephen Krebs, PhD, started at David G. Leach Research Station in 1992 and has been the director of the Leach Research Station since 1998. He received his bachelor's degree in history at the University of Chicago and his doctorate in plant breeding and genetics/horticulture from Michigan State University. Work at the Leach Station centers on the development of ornamental rhododendrons that are adapted to difficult conditions. Research in support of this goal includes investigations of cold and heat tolerance, identification and transfer of disease resistance, and adaptations to brighter (sunnier) growing conditions.
Sarah Kyker, PhD, is a microbial ecologist interested in the influence of human and natural environmental changes on microbial communities and their function. Kyker received bachelor's degrees in botany and secondary education from Miami University (Ohio) in 2003. Her graduate work was conducted in biology at Case Western Reserve University and resulted in a master's in 2006 and a doctorate in 2010. Sarah has been with The Holden Arboretum since 2007, where she completed her doctoral research under the advisement of Research Department Chairman David Burke. She is currently a postdoctoral scholar at Holden working with Burke and scientist Kurt Smemo.
Sheryl Petersen, PhD holds a bachelor's biology from Hiram College and an master's and doctorate in biology from Case Western Reserve University. Peterson is a plant ecologist whose research focuses on the roles natural and human-generated disturbance play in shaping vegetation patterns. She is particularly interested in how understanding the effects of disturbance can help provide a scientific basis for restoration of plant communities. She is currently a post-doctoral research associate at The Holden Arboretum and Case Western Reserve University
Ann Rzepka, horticulturist at The Holden Arboretum since 2008. Rzepka maintains the Myrtle S. Holden Wildflower Garden, collects and propagates seed for use within the garden, assists conservation staff with the heritage species monitoring program, and helps maintain Holden’s commitment to the Center for Plant Conservation and the preservation of rare and endangered plant species. She was previously employed by the Geauga Soil and Water Conservation District where she served as their Natural Resources Specialist. She earned a bachelor's degree in environmental studies from Hiram College.
Kurt Smemo is an ecosystem ecologist at The Holden Arboretum and an adjunct assistant professor at Case Western Reserve University and Michigan State University. His studies involve how soil microorganisms control organic matter decomposition and nutrient availability in forest and wetland ecosystems, and how those organisms respond to environmental change. Smemo has earned his bachelor's degree in forestry at the University of Montana, his master's in environmental science at the University of Illinois and his doctorate in ecology from Cornell University.
Susan Swisher, Holden's librarian, is a Northeast Ohio native who received her master's in library science from Case Western Reserve University. She began her career as a reference librarian at the Cuyahoga County Public Library. She spent several years in San Diego managing a cooperative library system before returning to Ohio.
Rebecca Thompson, Growing Students and Science program coordinator, has been with the Education Department at Holden since 1999 and has worked in environmental education for many years. She coordinates the Growing Students and Science Program, a community partnership to build interest and ability in the sciences in public school systems, and leads Holden’s Junior Birders Club for children and teaches a number of children’s classes. She received her bachelor's degree in biology at Kent State University.
Charles Tubesing, chief horticulturist, is a graduate of Purdue University. Tubesing has been with Holden since 1986. He is responsible for the development of Holden’s plant collection, having extensive experience and interest in the selection of appropriate woody plants to fit specific landscape criteria and in plant propagation with a special interest in magnolias.
Michael Watson, conservation biologist, started at Holden as a conservation seasonal three years ago. He earned his bachelor's degree in biology from the College of Wooster and his master's in ecology and evolutionary biology from the University of Michigan. He spends most of his time on the deer browse project, a large-scale, long-term study attempting to measure the impact of deer on Holden's forests. He is also the coordinator for Holden's Bluebird Project, which relies on 50 volunteers to monitor and band bluebirds, tree swallows and other secondary cavity nesting birds that use more than 200 nest boxes on the Holden properties.
Marian Williams, manager of public programs, has been with Holden since 1987 and is responsible for Holden’s public programs and interpretation of the gardens and natural areas as well as a variety of other special projects. She received her undergraduate degree from Earlham College and her master’s degree from Purdue University.
Luke Williamson, is a two-year education intern at Holden. He recently graduated with an undergraduate degree in environmental education and interpretation from the University of Wisconsin-Stevens Point. He has spent summers working as an educator for Western Arctic National Parklands in Alaska and the Spring Mountains National Recreation Area in Nevada.
Greg Wright, nursery supervisor, is in charge of plant propagation at Holden. He earned his bachelor's degree in horticulture at Brigham Young University and his master's degree in landscape architecture at Utah State University. Wright has been with Holden for eight years and teaches a variety of classes on horticulture and landscape architecture.
Non-Staff Instructors
Ian Adams is an environmental photographer, writer, and teacher specializing in natural, rural, historical and garden areas in Ohio. Since 1985, more than 6,000 of his color photographs have been published in books, posters, calendars, magazines and other publications. Ian has published 18 photography books and conducted more than 175 photography workshops and seminars. His books include The Holden Arboretum (University of Akron Press, 2000), Backroads of Ohio (Voyageur Press, 2006), Our First Family's Home: The Ohio Governor's Residence & Heritage Garden (Ohio University Press, 2008), Missouri Botanical Garden: Green For 150 Years (Missouri Botanical Garden Press, 2008) and A Photographer's Guide to Ohio (Ohio University Press, 2011) He lives in Cuyahoga Falls with his tabby cat, Fuji.
Pat Biliter comes from a long line of eastern Kentucky coal miners and broke family tradition to become a geologist. After completing his undergraduate and graduate studies at the Ohio State University and UCLA, and Airborne and Ranger training at Fort Benning, Georgia, Biliter spent the next 30 years overseas working for the Army Corps of Engineers. Among other assignments, he served as the Deputy District Engineer of the Europe District in Wiesbaden, Germany, where he was responsible for military construction, humanitarian relief and host nation assistance in 90 European, African, Middle Eastern and southwest Asian countries. After retiring from federal service in 2001, he settled in Cleveland, Ohio, and within a year became a school guide at the Holden Arboretum. Inspired in high school by the writings of John Muir and Rachel Carson, Pat quickly realized that the Holden Arboretum was a perfect setting to share his lifelong love of natural history and conservation with coming generations of young Americans. Biliter is also an Ohio Certified Volunteer Naturalist.
Judy Churchill, AYT, RYT, CYT, an accredited yoga teacher of Satyanada Yoga and registered as an RYT at the 500-hour level with Yoga Alliance. In 2001, she received formal initiation in India from Swami Niranjanananda Saraswati and given the spiritual name, Jayasri. She later earned a level two accreditation from Satyananda Yoga Academy, Mangrove Mountain, NSW, Australia. Churchill maintains a website with book reviews and articles on yoga at www.yogic-wisdom.com
Dan Donaldson is the district administrator of Lake County Soil and Water District. Having earned his bachelor's degree in environmental management from Cleveland State University, he assists local governments, landowners, and partner agencies with natural resource planning objectives, including special projects, ordinances, programs, conservation easements, program planning, administration and grant writing.
Denise Ellsworth, directs the honey bee and native pollinator education program through the OSU Department of Entomology on the OARDC campus in Wooster. In this outreach position, she supports and teaches beekeepers, farmers and gardeners through a variety of workshops, written materials and electronic resources. She earned her master's at Ohio State University, School of Natural Resources and bachelor of science from Ohio State University's Department of Plant Pathology. She is also a garden writer for the Akron Beacon Journal. .
Bob Faber has been a consultant to conservation and environmental organizations throughout the region. He leads natural history programs across the United States.
Susan Gray Bé, director of the School of Art at Fairmount Center for the Creative and Performing Arts, earned her master's in painting at the State University of New York at Albany, bachelor's in studio art at Hamilton College and studied at National Academy School of Fine Arts, University of Vermont and the Rhode Island School of Design. Having taught oil painting and drawing at the Fairmount Center for five years, she finds time to teach at the Cleveland Botanical Garden and the Cleveland Museum of Art as well.
Alec McClennan is founder and president of Good Nature Organic Lawn Care, a firm specializing in naturally-based, organic fertilization and natural weed control for lawns, trees, and shrubs on residential and commercial properties. Good Nature offers a full line of organically-based lawn and tree care services centered around proprietary, feed-grade formulas and processes that require no toxic chemical applications. Since its establishment in 1999, Good Nature has provided homeowners and commercial clients in the Cleveland community with the security of organically-based alternatives for naturally beautiful, healthy lawns and trees. McClennan is a member of the Ohio Lawncare Association, the Sierra Club and the Better Business Bureau. Alec has made numerous presentations regarding the organic care of lawn and landscape to homeowners' associations, garden clubs and at expositions. He continues to welcome the opportunity to share his knowledge and experiences with interested groups or organizations.
Haans Petruschke is a leader for the Audubon Society's annual spring bird walks at Holden. He has a bachelor's degree from the American University.
Gunter Schwegler is a fiber artist specializing in silk painting. His work in watercolor, acrylic and oil painting formed the basis of his style and technique. His recent work includes framed silk paintings, wearable art, banners, stage and set design, home furnishings, CD covers and public art space. His work is featured in “Creative Silk Painting” by Jan Janis and Diane Tuckman.
Sabrena Schweyer, FAPLD, is vice president of Salsbury-Schweyer, Inc. Akron Ohio. She is a national award-winning landscape designer, a certified permaculture consultant, a well known lecturer on sustainable landscaping, and a guest columnist for the Cleveland Plain Dealer. Sabrena is passionate about connecting people and nature in a way that nurtures both. She has more than twenty years experience in a variety of horticultural environments, including the gardens of England's National Trust. Studies at Oxford in England introduced her to the concept of the garden as an art form. Her diverse education incorporated agriculture, horticulture, history and the arts. Sabrena enjoys teaching, writing, photography and is especially fond of traveling in search of the world’s most beautiful places.
Renell Simrau learned to weave baskets from her grandmother at the age of 10. Simrau started teaching basket classes as a naturalist for the Wood County Park District in Perrysburg, Ohio and is a naturalist for Cleveland Metroparks. When not working, she enjoys bird watching, hiking, performing in the community theater, and sailing
Barbara Tercek, RYT, a certified yoga instructor and social worker is studying for her certification in yoga therapy.
Lynn Zocolo, horticulture educator at Fellows Riverside Gardens since 2002, is a graduate of Kent State University with an associate degree in horticulture technology. Zocolo is also an OSU Master Gardner.
