Alex Simmons, PlantRight Program Manager

Alex Simmons is based in Sacramento, CA. She has been the PlantRight program manager since October 2019, when she oversaw the transition of PlantRight from Sustainable Conservation to Plant California Alliance. In 2021, she re-launched the PlantRight spring retail nursery survey, and shortly after was promoted to Associate Director of Plant California Alliance. In addition to the Plant California Alliance, Alex is also the Executive Administrator for International Plant Propagators Society–Western Region. She holds a Bachelor’s degree in Sustainable Agriculture and Food Systems from the University of California, Davis. Her background in both sustainable agriculture and landscaping gives Alex a well-rounded view of horticulture and a deep understanding of how plants shape our world.

John Greenlee

John Greenlee is an internationally known landscape designer, horticulturist, author, and nurseryman specializing in the cultivation and study of grasses and grass-like plants. An expert on grass ecologies worldwide, he has been a passionate, potent champion of sustainable design and planting schemes for more than 30 years. His unyielding advocacy for saving the planet, for restoring a balance in and with nature is well said in his meadows mantra.

Katherine Renz

Katherine Renz is an MFA/MA student at San Francisco State focusing on personal essay, natural history, and humor. When she isn’t cycling through the city and trying to talk with plants, she is out exploring California’s wilder lands. Under the pen name Lady Lonicera, she crafts and publishes zines for sale at local bookstores including City Lights and the bilingual Medicine for Nightmares in the Mission District.

Erica Browne Grivas

Erica Browne Grivas is a lifelong gardener and journalist who has been schooled by plants on both coasts. Her feature articles appear in publications including the Seattle Times and Horticulture magazine, and a garden column for Pacific Publishing in Washington. Her writing has earned gold and silver medals of achievement from Garden Communicators International.

Adam Graves

Adam Graves is the Director of Horticulture at the San Diego Zoo. He oversees the plant conservation work, landscape management and agricultural teams of the organization. He is a lifelong ‘plant nerd’ and enjoys learning about all plant groups, but has a special fondness for bamboos and carnivorous plants.

Steven Haddock

Steven Haddock is a Senior Scientist / Marine Biologist at the Monterey Bay Aquarium Research Institute (MBARI).

Steve is working on deep-sea gelatinous zooplankton. He is doing research on bioluminescence, biodiversity, and ecology of deep-sea and open-ocean ctenophores, siphonophores, radiolarians, and medusae. In addition to assembling phylogenies for these groups, he is interested in cloning novel photoproteins and fluorescent proteins from these jellies. See publications for more details.

Steve’s educational background includes a B.S. from Harvey Mudd College and a Ph.D. from the University of California, Santa Barbara. He also holds an adjunct professorship in the Ecology and Evolutionary Biology department at the University of California, Santa Cruz.

Studio Petrichor

Studio Petrichor aims to mitigate the effects of climate change and strengthen your relationship to the landscape through thoughtful design, ethical practices, and nature-based solutions. Visit:

Leigh Adams

Leigh is an educator and eco-sensitive designer. She has been a horticultural interpreter at the LA County Arboretum and Botanic Gardens for many years and until Covid, has trained many county agencies in regenerative practices. She has conducted hands-on workshops with local schools, private citizens and professional groups. Her love of collaboration and education infuse all aspects of her work, leaving participants with a profound sense of empowered accomplishments.

Laura Allen

Laura Allen is the author of Greywater, Green Landscape: How to Install Simple Water-Saving Irrigation Systems in Your Yard and the co-founder of Greywater Action and has spent the past 20 years exploring simple and ecological water solutions. She is the lead author of the San Francisco Graywater Design Guidelines for Outdoor Irrigation, and authored The Water-Wise Home: How to Conserve and Reuse Water in Your Home and Landscape (Storey Press, 2015) and Greywater, Green Landscape (2017). She has a BA in environmental science, a teaching credential, and a master’s degree in education. Laura leads classes and workshops on rainwater harvesting, greywater reuse, and composting toilets. Laura has presented widely on greywater reuse, including at the Water Smart Innovations Conference, Bioneers, California Environmental Health Association conference, and California Landscape Contractors Association conference.

Shawn Maestretti

Designer, plantsman, licensed landscape architect and contractor, certified arborist, certified permaculture designer, educator, and environmental steward. Shawn has been creating exceptionally designed and artfully developed gardens in both California and Nevada since 2006. Highly collaborative with a strong attention to detail and a knack for problem solving, he helps his clients realize outdoor living spaces that they will connect with for years to come. Shawn combines extensive horticultural experience, strong composition skills, and a deep knowledge of regenerative practices with a wide palette of visually and texturally interesting climate-appropriate plants, breathing new life and a sense of place into every garden. Visit Studio Petrichor (

Winnie Hwo

Winnie Hwo is a Senior Public Engagement Specialist with the David Suzuki Foundation in Vancouver, British Columbia, Canada.

As a journalist, Winnie was trained to keep an open mind. As a public engagement specialist, she learned to never under-estimate the generosity of people. Working with volunteers from the Butterflyway Project and Sustainable Diversity Network, Winnie is hopeful we will be the solution to nature as we all want the same thing – a clean and vibrant environment for ourselves and our loved ones.

Noel Kingsbury

Dr. Noel Kingsbury is an acclaimed garden designer, writer and long-time collaborator of the renowned designer Piet Oudolf. With Annie Guilfoyle he runs the highly successful Garden Masterclass. Noel is a leading figure in naturalistic planting design and writes widely on this and related topics.

Join Pacific Horticulture and Noel Kingsbury Live for the Release of his latest book, Gardens Under Big Skies: Reimagining Outdoor Space the Dutch Way, on Wednesday, May 4, 2022, starting at 12:00 p.m. PT – click here for more information