Executive Committee Members



Landscape Architect

Mr. Casey has 15 years of experience serving both public and private-sector clients. His public-sector project experience includes masterplanning through implementation for public realm projects, cultural facilities, and historic sites that include secure federal campuses, courthouses, and museums. Private-sector projects include corporate headquarter facilities, urban streetscapes, and highly amenitized mixed-use and multi-family residential projects. In addition to projects throughout the Mid-Atlantic region, Mr. Casey has provided landscape architecture services for international projects in over 15 countries, including numerous new U.S. Embassy Compounds and Consulates. Michael specializes in managing projects from concept design through implementation, and leading multi-disciplinary teams on complex developments that integrate rooftop and courtyard amenities, perimeter security elements and advanced storm-water management solutions.

Michael earned his BLA in Landscape Architecture from Virginia Tech and is a Registered Landscape Architect in Maryland and Virginia.

Immediate Past President


Senior Landscape Architect

Stephen K. Cook, ASLA, LEED AP O+M began his career with a national design/build firm in 1987 after receiving his Bachelors of Landscape Architecture from Mississippi State University, and has worked as a landscape architect with planning, engineering and architecture firms in the Washington Metropolitan area since 1987. The diverse experiences Steve has had in his career, helped him gain a detailed understanding of the design process from conceptual through construction documents, construction management and ultimately the ongoing maintenance. In addition to his role as a landscape architect, he also is involved in planning and entitlement work.

In addition to his professional duties, Steve serves on USGBC’s Sustainable Sites Technical Advisory Group, Water Efficiency Technical Advisory Group and served on the SITES Technical Subcommittee for the recently unveiled SITES Rating System.



Landscape Designer

Kerri designs residential and small-scale commercial projects in the metropolitan Washington, DC area. She has also been responsible for project management and crew oversight. Kerri has consulted with over 800 individual clients and successfully completed over 300 design/build projects. She enjoys working with people and is dedicated to each of their unique visions and needs.

Kerri graduated in 2011 from the College of Environmental Science and Forestry in Syracuse, NY with a Bachelor’s Degree in Landscape Architecture. She was an active member of the ASLA Student Chapter and served consecutive terms as Secretary and President of the chapter. Kerri has been an active member of the Potomac Chapter for the past 5 years, serving as member-at-large, committee chair, and president-elect.



Landscape Architect/PB

Rob Tilson, FASLA, PLA has held many positions for the Potomac Chapter. Most notably, he has served as a two-time President from 1993-1994, two-term Trustee from 1998-2003. While serving in these capacities, Rob represented the chapter on the Virginia Licensure Committee (1998-2001), 100 Parks/100 Years Program Committee (1998), and the Centennial Medallion Program Committee (1998). Rob also instituted and re-organized the Nominating Committee for the Chapter and served as Chairman from 2002 to 2003. He co-chaired the Host Committee for the 2010 ASLA National Meeting in Washington, DC.

Nationally, Rob has served in several capacities including ASLA Vice-President of Professional Practice from 2004-2005. During his tenure as Vice President, Rob helped launch the SITES initiative and revamped the Professional Practice Network program and led the Archive Committee to help establish the Fellows database. Rob also served as the Board of Trustees Representative on the Landscape Architecture Foundation Board (2003). In 2005, Rob was recognized as a Fellow for his service to the profession.

As Chapter Trustee, Rob will concentrate on increasing Chapter visibility with other allied professions, work to finalize our licensure status with the District of Columbia and serve as a leader within the ASLA Board of Trustees.

Rob received his Landscape Architecture degree from Purdue University and has been practicing landscape architecture in the Washington, DC metro area for over 30 years. Rob is licensed in Virginia.



Landscape Architect

Steve McLaughlin is a landscape architect from Silver Spring, Maryland, who has been practicing in the Baltimore/Washington National Capital Region for nearly twenty years.  Since January 2015 he has been fulfilling a contract with the State Department to provide subject matter expertise in landscape architecture as a supervisor of site design for American diplomatic missions world-wide, and as a code official for landscape-related design standards.

Steve has previously been employed with several architecture, engineering, landscape architecture, and other consulting firms of various sizes; serving a broad mix of clientele including the State Department, Department of Defense, and other federal agencies, for domestic and international projects ranging very widely in scale and scope.  In a self-employed capacity he has also designed residences, additions, decks, patios and gardens.  His first career was as a U.S. naval officer.

Steve has a bachelor’s degree in architecture from the University of Virginia and a master’s degree in landscape architecture from Louisiana State University; is certified by CLARB; and professionally registered in Maryland.  He was previously affiliated with the Maryland Chapter ASLA, for which he also served as Secretary.



Landscape Architect

David received his Master of Landscape Architecture degree from the University of Virginia in 2008. In the private sector he has worked for local firms Michael Vergason Landscape Architects and Campion Hruby Landscape Architects. David recently formed his own firm, David Wooden Studio LLC, working on a combination of commercial, environmental and residential projects. In the public sector he worked for the District Department of Energy & Environment (DOEE). At DOEE he managed green infrastructure implementation projects on public lands (parks, schools and PROW) and private properties. He also helped coordinate the Green Area Ratio program as a training instructor, guidance author and plan reviewer. He is a Registered Landscape Architect in Maryland. His professional interests include green infrastructure, sustainability and parametric modeling.

Prior to becoming a landscape architect David was a Certified Public Accountant licensed in the District of Columbia and Kentucky. He worked for the financial services firm PricewaterhouseCoopers for 13 years with specialties in taxation and technology. He has a Bachelors and Masters in Accounting from the University of Kentucky.


Landscape Architect

Laurie Beth Donnachie earned a Bachelor’s of Landscape Architecture from The Pennsylvania State University in 2011. She is a licensed landscape architect in Virginia and Pennsylvania.  Laurie is also an ISA certified Arborist and holds a certificate in Healthcare Garden Design.  Her work experience includes many phases of residential development spanning from neighborhood layout through private garden installation.

Landscape Architect

Carla Ellern, ASLA, LEED® AP BD+C is a registered landscape architect with Lila Fendrick Landscape Architects in Chevy Chase, MD. She received her Master’s in Landscape Architecture from the Graduate School of Design at Harvard and would like to spread the word about what landscape architects do through her involvement with Potomac ASLA. In the public sector, she worked for the Department of Environmental Protection (DEP), Montgomery County, Maryland in the RainScapes program where she worked with homeowners and communities to reduce stormwater runoff. She’s interested in improving the environment and people’s lives by expanding green infrastructure and sustainability in our landscapes.

Associate, MVLA

Matthew Johnston is a registered landscape architect with MVLA, an award-winning design firm in Alexandria, VA.  He received his Masters of Landscape Architecture and Masters of Urban Planning degrees from Virginia Tech, and is an enthusiastic member of the professional design community represented by the Potomac Chapter of ASLA.

Matt’s background in international relations, urban planning, and landscape architecture informs his commitment to bring the benefits of design to more people.  His interest in expanding the impact of his work led him to the field of public interest design, where he volunteers as a project leader with Open Architecture DC, a pro-bono design non-profit.  He previously served as Chapter Coordinator for the DC chapter of Architecture for Humanity, and he’s a member of the Potomac Yard Design Advisory Committee for the City of Alexandria, helping to shape development in a growing urban corridor.

Matt serves as the Potomac Chapter Mentorship Chair, helping to connect students at Virginia Tech’s Washington-Alexandria Architecture Center with professionals in the Chapter.

Capital Projects, Planning & Design, DC Parks and Recreation

Peter has been living and working in Washington for over fifteen years. He has been happily employed by DC DPR for over three years and has assisted the department with the management and construction of many award winning facilities and parks within their ever expanding portfolio.  He has active oversight of over twenty projects per year and engages the local community as a city representative. Peter helps to develop high level concept designs, while managing projects ranging from aquatic facilities, fields, playground and recreation centers, ensuring that DC consistently ranks as one of the top five cities in the nation by the Trust for Public Lands, which promises the public has great access to parks.

With a background in green infrastructure, Peter also focuses on green roofs and storm-water management. He has partnered with firms across the country while employed with the Tilson Group to work on high security government facilities including the Pentagon, the Homeland Security & Coast Guard Headquarters and the East Wing of the National Gallery of Art. Peter was also the principal of his own design/built practice for seven years and worked on projects of various complexities, ranging from private residences to embassies, government such as the Vice President’s Residence, and commercial properties.

Peter has a degree in landscape architecture from UMass, Amherst.  Peter has also volunteered as technical advisor with Engineers Without Borders at the University of Maryland and in Ecuador. He has guest lectured at the University of Maryland in their Engineering and Landscape Architecture Departments and at Catholic University of America in their Architecture school. He has also operated in Germany, South Sudan and Sudan with foreign contractors and as a private consultant. He was also the treasurer of his student ASLA chapter.

Partner, LandDesign

Stephanie is a Partner and Landscape Architect with LandDesign, based out Alexandria VA. Stephanie directs many of the firm’s large scale master planning projects, including long-range master planning to urban design solutions for some of the nation’s leading developers. As a creative design leader, she applies her knowledge by offering innovative approaches including state-of-the-art design tools to engage diverse stakeholders in building consensus and understanding. She enjoys working at a variety of scales throughout the design process, and remains uniquely involved in all stages of a project. Her experience includes urban design, park planning and design, community master plans, site planning, design guidelines and streetscapes, with an emphasis on utilizing green infrastructure techniques as storm water harvesting, roof gardens, stream restoration, native plants and natural treatment systems for bio-retention.  Several notable NCASLA and Tri-State chapter award winning projects include Camp Lake James, the Park at Pine Hill Business Campus and Dr. Wesley Grant Southside Center.  She currently is very involved in the design of several Tysons VA redevelopment projects.

After receiving her BLA from the University of Georgia in 2000, Stephanie spent the first portion of her professional career in California.  Stephanie has been a member of ASLA since 2005 when she was on an “emerging professional” panel at the Fort Lauderdale, FL Annual Meeting & Expo.  She currently participates on the ASLA national PR and Communications Advisory Committee, recently completed an ASLA 2015 Tellers Committee Appointment and in May 2014 served as a juror for the Virginia Tech MLA student awards at the WAAC (Washington + Alexandria Architecture Center).  Additionally, prior to moving to DC in 2011, she served as Mountain Section chair for the 23 western counties of the NC Chapter of ASLA and was a City of Asheville NC Greenway Commissioner.  She is currently active in several DC metro area organizations and initiatives including Built by Women DC, Urban Land Institute and the City of Alexandria VA Public Art Task Force.

A fun fact about Stephanie is that she was the unnamed “architect” who sketched an “instant city park” in this Washington Post story – here.

Director/Landscape Architect, Rhodeside & Harwell

Elliot had a dream over 30 years ago of establishing a noteworthy multi-disciplinary landscape architecture, planning and urban design practice. Through collaboration with his founding partners, Deana and Faye, he has realized his goal: the creation of a talented, respected firm with an outstanding staff doing creative and carefully considered work locally, nationally and internationally. Elliot is passionate about landscape architecture. He grew up wanting to be an architect initially, then evolved that dream into fine arts and industrial design. After hearing a lecture by Ian McHarg when he was a sophomore at the University of the Arts, however, he was inspired to pursue a different career in “the arts” — a Masters in Landscape Architecture from the University of Pennsylvania. Following more than a decade of practice in Philadelphia, London, Boston and Washington, DC, he and his partners established Rhodeside & Harwell in 1986.  Following his life-long interest in the diverse challenges presented by different scales of work, Elliot currently leads design and planning projects ranging from gardens to regions. He is happiest when the projects are complex, the stakeholders are many and the assignments are full of challenges. He loves mentoring staff and maintaining a high creative bar from which each project is measured. He is proud of his and his firm’s work and the positive impacts it has had on the lives of many.

Landscape Architect, Smithsonian’s National Zoo and Conservation Biology Institute

Matthew Sellers is an 18-year resident of the DC area, moving here from Ohio for graduate school at Virginia Tech in Alexandria, VA. His education is in urban planning and landscape architecture. He is a landscape architect licensed in the state of Maryland, and member of ASLA. His professional history includes work with the landscape architecture firms Sephenson + Good (9 years) and Clinton & Associates (5 years). He also taught courses in the Landscape Design and Sustainable Landscapes program at George Washington University (12 years). Matthew’s experience includes the design and construction administration of residential gardens, public plazas, playgrounds, perimeter security master plans, multi-acre mixed-use neighborhood developments, and animal habitats. Currently he works in the Office of Planning and Strategic Initiatives at Smithsonian’s National Zoo providing thoughtful and creative planning and design solutions for the Zoo’s visitors and inhabitants.

Project Manager and Landscape Architect, STUDIO 39 Landscape Architecture

The foundations of Abby’s career lie in her interests of sustainable design and the impacts of environmental and social geographies in the landscape. She is an alumnus of Penn State University, where she obtained a BA in Landscape Architecture and minor in Geography. Her education fed her curiosities of how people relate to the landscape and use outdoor spaces, as well as the social and cultural aspects that societies have on the land at all scales. She has found the DC area to be rich in opportunities to exploit her interests and use her design skills and education to create spaces for everyone.

Both her degree and minor were complimented by studying abroad and exploring places in North America, Europe, and Africa. Abby has experience in community design as well as high-end residential design in the Chesapeake Bay region. She is currently a Project Manager and Landscape Architect at STUDIO39, where she works primarily on mixed use projects, multi-family residential, and some private residential projects. Additionally, she does some project photography and is involved in some office marketing endeavors. She is a member of the Potomac ASLA Emerging Professionals Committee, likes to volunteer her time to the community when she can, and also takes interest in personal endeavors involving graphic design and photography.

Associate, Lee and Associates Inc

Annie Varma is an Associate with Lee and Associates, a landscape architecture firm based in Washington D.C. She holds a Master’s degree in Landscape Architecture with a minor in Cultural Heritage and Museum Practices from the University of Illinois at Urbana-Champaign, and a Bachelor’s degree in Architecture from India. Over the past 8 years as a professional, she has worked in diversified Landscape Architecture, Historic Preservation, and Architecture & Planning firms and brings the knowledge of Heritage Conservation and waterfront design based on her graduate study. She has published her work twice and actively pursues and researches green and sustainable initiatives, in both her urban design projects and professional development pursuits. Her current work includes a broad spectrum of projects ranging from memorial, mixed-use residential, playgrounds and parks, streetscape and public realm design, and master planning projects. She also loves to volunteer for community causes and providing pro-bono graphic design assistance to emerging entrepreneurs.

Executive Director

Susan Newman

Prior to being named Executive Director of the Potomac Chapter of ASLA, Newman served as Executive Director of Corporate Facility Advisors (CORFAC International), an alliance of entrepreneurial commercial real estate firms. For more than 20 years, she was Secretary General (CEO) of the U.S. Chapter of the International Real Estate Federation (FIABCI), also serving as interim Secretary General for the international body during part of that time.

With more than 30 years in association management, Newman works with boards and volunteers and is responsible for the administration of the association, as well as membership retention and services.