Dan Weber, WPIT

President • Environmental Consulting Lead

Dan Weber is a founding member of PGC and leads our Environmental Consulting services. He holds a B.S. in Biogeosciences from the University of Tulsa and a certificate in Wetland Science and Management from the University of Washington. He is certified by the Society of Wetland Scientists as a Wetland Professional in Training (WPIT). He brings an interdisciplinary vision and zeal for science communication to his work in the built environment.

Bret Kenney

Estimator • Preconstruction

Bret Kenney is a founding member of PGC. He develops scopes and estimates for residential, environmental, and public projects - translating site conditions, constraints, and cost drivers into clear plans, budgets, and buildable next steps. His focus is constructability and sequencing: turning site conditions into something that can be priced, scheduled, and executed. Off the job, he’s usually in the mountains.

Miranda Holtgrefe

Horticulture Program Manager

Miranda has a background in sustainability and experience in estate and mature gardening, plant identification, and program management. She is a certified Master Pruner. She is excited to be part of the PGC family and is looking forward to planting her roots here. When she’s not working, she enjoys spending time reading, writing, hiking, photography, foraging, kayaking, backpacking, attending concerts, practicing yoga, and hanging out with her dog Lily.  

Faye Williamson

Construction Project Manager

Faye has worked on the PGC construction crew since 2023. She has three additional years of experience working as a landscaper for a local school district. She is skilled with a chainsaw and large machines, and also has a passion for metalworking.

Marco Downs, CPH, EcoPro

Landscape Designer

Marco is a Certified Professional Horticulturist and holds two degrees in architecture. He has worked in the green industry since he transplanted himself from Florida to Seattle in 2014. At PGC, he leads our design team. Marco makes an effort to maintain a connection to the land and community through participation in the P-Patch program, the Beacon Food Forest, the Cass Turnbull garden, and by serving on the board of directors for Plant Amnesty. Marco constantly seeks to expand his horizons through art and continuing education. His interests include acrylic painting, mycorrhizal communication, and cymatics.



Ryan Riley

Business Development • Client Intake

Ryan sees possibilities where others see problems, and uses creativity and strategy to transform ordinary spaces.

Jonathan Henderson, CPH

GSI Specialist • Construction Team

Jonathan is a founding member of PGC. He is a Certified Professional Horticulturalist, Paver Installer, Permeable Specialist, and SRW Installer. Jonathan has a passion for all things green and growing, building beautiful landscape structures. He is an experienced and creative carpenter.  From the science of soil structure to the relationships of plants and beneficial fungi, Jonathan's boundless curiosity keeps him learning and expanding his skills daily.

Melissa P, CPH

Horticulture Team Lead

Melissa is a founding member of PGC. She is a passionate Certified Professional Horticulturalist. She brings vast horticultural knowledge to PGC with both decades of field experience and an educational background in Environmental Horticulture at Lake Washington Institute of Technology.

Bonnie Henwood, CPH

Arborist Trainee • Construction Team

Bonnie is a Certified Professional Horticulturalist, Paver Installer, Permeable Specialist, SRW Installer and an ISA arborist-in-training. She has a bachelor's degree from UW in Ecology, Evolution, and Conservation Biology. She discovered that environmental construction combined her love of plants with her passion for creating with her own hands. She has taken carpentry courses at the Seattle Wood Technology Center and is always growing her skillset. Building beautiful spaces for people to enjoy nature is integral to her work. In her free time, she has many hobbies including gardening, bookbinding, painting, and leatherwork.

Robert Engel, CPH

Horticulture Team Lead

Robert is a Certified Professional Horticulturalist. His emphasis is pruning in the natural style, and strategically reducing site maintenance requirements over time. He is an active student at Edmonds College, focusing on plant identification and arboriculture. He has a direct, proactive style, seeking to find the most practical and horticulturally accurate solution to everyday garden challenges. In his free time, Robert is a community organizer.

Joshua Poisson-Smith

Horticulture Team Lead

Jenna Travis

Irrigation Specialist

Jenna has more than a decade of experience in landscaping and irrigation with certifications in Landscape Sprinkler System Design, Evapotranspiration, and Plant-Soil Based Relationships. She has overseen the design, installation, and management of smart irrigation systems for more than a decade and is passionate about water conservation. Fun facts: boxed competitively for many years, Forrest Gump makes her cry, she has 2 amazing kids, married her best friend, and manages a clean and sober living community for recovering addicts.