Clackamas County Master Gardeners

Monthly Lecture Series

We hold free lectures on the 2nd Monday of each month (except July and August) at the Milwaukie Center (5540 SE Kellogg Creek Drive in Milwaukie). Lectures are open to the public and start at 7 p.m. 

If you have a physical disability that requires special considerations in order for you to attend the event/activity, please notify the metro Master Gardener program at 503-655-8631 or 

Master Gardener Volunteers: Now it's easier to get your recertification hours. Tagged lectures can be applied toward your Master Gardener program training requirements. Lectures will be marked with *MG education credit*


September 11:

Of Moss and Men - Sarah Jovan, USDA Forest Service

U.S. Forest Service scientists in Portland began a novel study in 2013 by using moss collected from urban trees to develop fine-scale maps of air pollution. Urban moss analysis potentially could revolutionize air quality monitoring by serving as an inexpensive screening tool to help cities quickly identify where to place pollution monitoring equipment. Earlier findings from this study contributed to new pollution controls, reexamination of the regulatory exemptions for the stained-glass industry, and the creation of a new state program, “Cleaner Air Oregon.”

Sarah Jovan is a research lichenologist and the lichen communities indicator advisor for the USDA Forest Service Forest Inventory and Analysis Program, and is part of the Resource Monitoring and Assessment Program within the Pacific Northwest Research Station in Portland.

*MG education credit*


 October 9:

The Sauvie Island Partnership - Jane Harline

Jane Hartline strongly believes gardeners can save the world!  She challenges us to put our passion for gardening into a high cause and will offer ideas from her work on Sauvie Island. Jane has lived on the island since the early 70s. As an avid birder and gardener, she is knowledgeable about the island’s diverse and abundant wildlife.  Upon retirement ten years ago, Jane began habitat restoration work on the island.  She founded the Sauvie Island Habitat Partnership and enlisted help from volunteers, landowners, public agencies, and non-profit organizations.

Among their achievements are planting meadow of wildflowers to restore grassland; surveying ponds to restore habitat for rare aquatic plants, Western painted turtles and native frogs; identifying ideal locations and securing landowner permission for new osprey nesting; and planting mixed hedgerows along the roads as habitat for pollinators and song birds. Join us as Jane helps us put the concept of ‘right plant, right place’ in a larger context.  Learn to set the stage for inspiration, relaxation and creature protection in your outdoor living space.

*MG education credit*


November 13:

Growing Conifers: What Gardeners Can Learn from Christmas Trees, Chal Landgren, OSU’s Christmas Tree Specialist

Many gardens include conifers such as Douglas, noble, grand, Nordmann or Turkish firs. Chal’s talk will focus on common problems that gardeners and Christmas tree growers share. Some of the problems may have a solution, others may simply be warnings to avoid future problems. He will also discuss some of the culturing tips that may be useful in gardens.

Chal Landgren is OSU’s Christmas Tree Specialist. Recent research projects include getting rid of slugs for tree export, foliar fertilization, genetic improvement and testing of noble fir, Douglas fir and Nordmann/Turkish fir. Frequent tree questions involve a wide variety of pest and tree problems and culturing. He and his wife run a small Christmas tree farm on their 7-acre farm. 

*MG education credit*


December 11:

Garden Art and Symbols, Steve Pettingill

Landscape Consultant and Horticultural Therapist, Stephen Pettengill will teach us the basics of symbolic references commonly found in natural settings as well as art selection and placement in the garden.  Whether you are considering a fountain, statuary, or just the understated power of a well-placed boulder, come and learn how this designer uses symbolism and art in customized environments.  Learn to set the stage for inspiration, relaxation and socializing in your outdoor living space.

Stephen Pettingill earned an interdisciplinary degree (Business, Gerontology, and Environments) from Marylhurst and completed a Horticultural Therapy program in Portland.  He also has a lifelong study of horticulture and design.


January 9:

This presentation was canceled due to weather concerns

Old Portland Gardens Through Hand-Painted Glass Lantern Slides - Matthew Cowan and Suzanne Bishop of the Portland Garden Club

The Oregon Historical Society is proud to present an original glass lantern slide show on the history of twentieth century gardens told through the lens of the Portland Garden Club. These slides were created locally by George C. Stephenson (1866-1940) on behalf of the P.G.C. – many of which document the famed Portland gardens of the time including the Kerr gardens and the Frank and Meier Estates. All slides have been delicately colored by hand and will be screened using an original lantern slide projector.

Matthew Cowan, archivist at the Oregon Historical Society, has preserved the slides and projector, can talk about his work, and will manage the presentation. Suzanne Bishop, of the Portland Garden Club,  will narrate the show using an original narration. This will be such a beautiful and important reminder of what Portland gardeners have found beautiful and important in our past!

Portland Garden Club

Oregon Historical Society


February 13:

Tree Hazards and Prevention - Paul Ries, Instructor and Extension Specialist at OSU

Every year our landscape changes as trees fall or break, causing property damage, injuries and power outages.  While some tree failures are unpredictable and unavoidable, many can be prevented.  Paul Ries, OSU Urban Forestry Instructor, shares tips on how to recognize the warning signs that trees may be in trouble so we can deal with potential problems and correct them before something bad happens.  Paul also will highlight planting the right tree in the right place, how to prune it correctly and caring for it properly throughout its life.

Paul Ries is the Director of the Graduate Certificate in Urban Forestry, Instructor and Extension Specialist at OSU.  He has over 25 years of urban forestry experience at the municipal, state, national, international, non-profit and academic levels.  At OSU, he teaches online urban forestry courses and is the lead curriculum developer for new undergraduate and graduate degree programs in urban forestry.  

*MG education credit*

Tree Protection on Construction and Development Sites OSU pub EM 8994

The Pacific Northwest Chapter of the International Society of Arboriculture (PNW-ISA)

An Oregon Homeowner's Guide to Tree Care


March 13

News & Opportunities for CCMGs - Gail Langellotto, Statewide Master Gardener Coordinator

Please join us as we learn about what's happening in the world of Master Gardening for our state and region. Gail will give a short talk about opportunities for gardeners in the coming year.

Google: Garden Ecology Lab

Email: Gail Langellotto (

April 10:

Contained Exuberance! Adding Style and Pizzazz to Container Gardening - Bob Hyland, Garden Designer

Bob Hyland loves plants and containers! As a designer of gardens and container planting, he creates designs that are plant-driven, exuberant, and sustainable. He combines ornamental plants happy in their environment and complementary to each home or space. His container designs have been featured regionally in New York’s Hudson Valley and Berkshire Mountains when he lived and worked there—even the New York Times—and now in Portland. Relying heavily on texture and foliage, Bob’s gorgeous containers thrive in sun or shade by design. He has suggestions for sustainability that are based on best containers, plants, and care; and of course suggestions for artful, exuberant designs! *MG education credit*

May 8:

Aging and Gardening - A Panel Discussion - Barbara Blossom Ashmun Patty Cassidy, and Carolyn Guinther will offer advice drawn from research and personal experience.

Popular garden writer and speaker Barbara Blossom Ashmun gardens on nearly an acre in Portland’s West Slope. Over the past decade, she has successfully transitioned her spectacular garden toward lower maintenance. Barbara wrote the garden column for the Portland Tribune from 2004 to 2011. She has written 6 garden books, most recently Married to My Garden, about her love affair with plants. Her seventh book, Love Letters to the Garden, is available on Amazon.

Patty Cassidy is a registered horticultural therapist. Her book, The Practical Illustrated Guide to Gardening for Seniors, published in 2012, was chosen by The Oregonian as one of the top five garden books that year. It won the American Horticultural Therapy Association Publication Award in 2013. Patty is President of the Portland Memory Garden and currently works with frail elders and older adults, especially those who have memory impairment. Patty is a life-long gardener, a Master Gardener™, and tends her large residential garden on Mt. Tabor.

Seasoned gardener Carolyn Guinther lives and gardens on nearly one acre in Aloha. Carolyn’s garden began in 1960 but the present one was formed in 1991. In recent years, Carolyn has transitioned her garden by incorporating choice shrubs and low-care perennials to simplify maintenance. Her garden continues to enjoy its reputation as a show place. Carolyn’s garden has opened many times for fundraising events, including twice for the Garden Conservancy Open Day. *MG education credit*

June 12:

Conserving our Bumble Bees - Richard Little

Bumble bees are iconic, native pollinators -- and many species are experiencing dramatic population declines throughout North America. Come learn what is being done to help conserve these essential pollinators, and what you can do to help!

Rich Little spent his career with the California Department of Food & Agriculture and is a volunteer instructor for the Master Gardener Program. He has a B.S. in entomology and has co-authored and co-edited publications on mason bees and oak forest invertebrates. In 2014 Rich served on the Oregon Joint Interim Task Force on Pollinator Health (HB 4139), the report submitted to House in Dec 2014. Rich has been a longtime supporter of The Xerces Society whose mission as an international nonprofit organization, protects our planets’ wildlife through the conservation of invertebrates and their habitats. *MG education credit*

Link to short film -- A Ghost in the Making --


click here for key points covered


Details and program notes from 2011, 2012, 2013, 2014, 2015, 2016


Clackamas County Master Gardeners are the folks who put on the annual Spring Garden Fair, bringing together over 7,000 gardeners with over 150 plant and garden-art vendors.

Oregon State University Extension Service offers educational programs, activities, and materials without discrimination based on age, color, disability, gender identity or expression, marital status, national origin, race, religion, sex, sexual orientation, or veteran's status. Oregon State University Extension Service is an Equal Opportunity Employer. In reference to publications, events, or activities: Publications will be made available in accessible formats upon request. Please call 503-655-8631 for information. If you have a physical disability that requires special considerations in order for you to attend the event/activity, please notify the metro Master Gardener program at 503-655-8631 or