Our practice is comprised of a talented and qualified staff of landscape architects and administrators with over 30 years of combined experience.  Our mission is to provide personalized and professional service to each of our clients.

Clinton & Associates’ founding principal, Sandra Youssef Clinton, FASLA is an accomplished landscape architect and horticulturist with over thirty-five years of experience in mixed-use, retail, commercial, institutional, and private residential design.  Her firm has won countless awards for their innovative use of building materials, acute understanding of outdoor scale, and extraordinary expertise and approach to planting design and plant culture.  Using sustainable practices, Sandy integrates her passion for plants and her background in horticulture and plant science with her innate talents as a designer of dramatic, contemporary, and seasonally-changing landscapes.  

Sandy launched Clinton & Associates in 1998, and continues to build meaningful landscapes and long-term client relationships.  Her work is strongly influenced by her lifelong relationships with Brazilian landscape architect, Roberto Burle Marx, and Philadelphia-based, Conrad Hamerman.  She spent the first 14 years of her career as Design Lead with Oehme, van Sweden & Associates in Washington, DC.  Echoes of these influential designers and mentors show up in the bold planterly approaches she expresses in each design.  

Sandy was awarded the prestigious Landscape Design Award from the American Horticultural Society; she is a Fellow of the American Society of Landscape Architects; and she serves on the Stewardship Council of The Cultural Landscapes Foundation.  Sandy is a nationally respected lecturer and is a visiting critic at the University of Maryland and The University of Virginia. She was recently keynote speaker for the Davidson Horticulture Society’s Annual Conference, and at the Nebraska Statewide Arboretum. syc@clinton-la.com

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Kate Ries, PLA, ASLA is a Principal at Clinton & Associates, PC, with 12 years of experience in designing and developing sustainable, practical, and sculptural landscapes for large urban and campus projects. Kate leads the design studio and manages a number of commercial and mixed-use projects. She is a detailed thinker, a strong designer, and a confident leader.

Kate received her Bachelor’s of Landscape Architecture from Philadelphia University where she had the opportunity to travel though Europe and South Africa. She has been involved in and led a wide range of award-winning projects including campus-wide landscape master plans, site specific institutional designs, and intimate residential gardens. Her aesthetic and inspiration have been influenced by her extensive travels as well as her love of art and nature. kries@clinton-la.com


Dan Cook, ASLA is a Landscape Designer assisting with commercial mixed-use development and residential projects; including site detailing, seasonal planting, and furniture design. Growing up on Long Island and attending college at The State University of New York College of Environmental Science and Forestry in Syracuse, Dan moved to the Washington DC area to join the Clinton & Associates and pursue his passion for creating vibrant, lush landscapes.   

Dan is particularly interested in urban design and planning, and is focused on large-scaled mixed-use development landscapes currently in the office. dcook@clinton-la.com


Xing Chen, ASLA is a Landscape Designer at Clinton & Associates.  He brings an interest in various project types and scales, and has always been seeking a balanced beauty in the natural and built environment. In addition to landscape architecture design, Xing is interested in photography, snowboarding, and travel. Xing earned his Master of Landscape Architecture degree with an ASLA Honor Award from Clemson University, and a Bachelor’s of Landscape Architecture from Beijing University of Agriculture in Beijing, China. Xing is fluent in Chinese and English. xchen@clinton-la.com





Mary Ann Allison is the firm’s Director of Administration and Marketing.  With a Bachelor’s Degree in Communication Arts and Design from Virginia Commonwealth University, Mary Ann contributes to the development of proposals, as well as media and public outreach, in addition to her lead financial and administrative responsibilities with the firm. mallison@clinton-la.com