PHYTO: Principles and Resources for Site Remediation and Landscape Design



Kate Kennen, ASLA and Niall Kirkwood, FASLA | Publisher: Routledge, Taylor and Francis Group


‘PHYTO’ presents the concepts and application of phytoremediation and phytotechnology in one comprehensive guide, illustrating when plants can be considered for the uptake, removal or mitigation of on-site pollutants on a range of landscapes such as brownfields, landfills and military sites. Current scientific case studies are covered, highlighting the advantages and limitations of plant-based cleanup. Typical contaminant groups found in the built environment are explained, and plant lists for mitigation are included. This is the first book ever to address the benefits of phytotechnologies from a design point of view, taking complex scientific terms and translating this research into an easy-to-understand reference book for those involved in creating planting solutions. Phytotechnology planting techniques are employed post-site contamination to help clean up already contaminated soils and groundwater of harmful toxins and chemicals. This book presents a new concept to create projective planting designs, ‘phytobuffering’ where future pollution may be expected.


So you’ve had your soil tested and it’s not good news. Can plants help remediate your site’s contaminants? Cost-effective Phytotechnology (phytoremediation) plantings can be effective in mitigating air, soil and water pollutants, but these interactions are complicated, sometimes taking decades for remediation, and many times plant-based remediation strategies are not a good fit for environmental cleanup. When do they work and when don’t they? There is a lot of confusion around what phytotechnology can and cannot accomplish. This confusion is exacerbated by a significant amount of outdated information available on the internet.

PHYTO: Principles and Resources for Site Remediation and Landscape Design (Book, Routledge, 2015) translates the science of plant-based remediation into an easy-to-read, daily desk reference for the professions of landscape architecture, planning, site engineering, real estate development, urban design, horticulture, and ornamental gardening. It presents the concepts of phytoremediation and phytotechnology in one comprehensive guide, illustrating when plants can be considered for the uptake, removal or mitigation of on-site pollutants. This is the first guide of its kind to translate the complicated peer-reviewed science from various journals and case studies to design practitioners. Previous books published on phytoremediation were written by scientists for scientists. The thick language, obscure terms and text-based format are difficult to navigate. Filled with legible tables, photographs and diagrammatic drawings, PHYTO guides the reader through the process of selecting plants for their aesthetic and environmental qualities, combined with their contaminant-removal benefits. The book publication was released in June 2015 and is available through commercial bookstores. The first printing (800 copies) sold out in December 2015 and the book is not in its second printing.

Major population centers around the world continue to become post- industrialized while manufacturing globally relocates to centers of inexpensive labor and materials. Cities previously focused on industry are shrinking and vacant land with contamination presents itself. In particular, sites that by virtue of past industrial uses are today contaminated, environmentally disturbed, ecologically threadbare and perceived as economically and socially dysfunctional need remediation to become habitable again.

Twenty percent (20%) of all real estate transfers in the United States are brownfield sites, (Sattler et al, 2010) with the current value of these lands in 2010 in the range of two trillion US. Dollars. The US EPA estimates there are approximately 450,000- 600,000 identified sites located across the country, although this number has been considered unrealistically low (U.S. Accounting office, 1992). More than 16% of global land areas, equivalent to about 52 million hectares, are impacted by soil pollution worldwide. (Anjum, 2014) All these sites, whether large or small, nationally or international need a wider range of cost effective solutions to clean-up or mitigate the risk of soils, ground water, sediments and existing infrastructure found there.

Remediation technologies are however very costly, preventing cleanup of contaminated brownfield sites. The majority of traditional remediation approaches are expensive and energy intensive in their approach to quickly correct an environmental problem that was decades in the making. The cost effectiveness of phytotechnologies versus traditional remediation industry approaches is often a significant advantage, and the long term energy required is often less since phytotechnologies typically do not require mechanical pumping systems, utility power, or much supporting infrastructure and equipment. Plant-based cleanup methods can be as little as 3% of the cost of traditional cleanup costs. (Glass, 1999)

However, in addition to utilizing phytotechnologies as a tool for site remediation, PHYTO considers how phytotechnologies can be also utilized as a preventative measure in the designed landscape. This moves the application of phytotechnologies away from laws and regulatory frameworks surrounding remediation activities towards a horticultural, design and planning related set of concerns. The design and installation of phytotechnology plantings can be based on anticipated pollution events to be determined. This publication is the first targeted towards the spatial design, form, structure and aesthetics of this technology, rather than simply the science behind it. The authors’ intent is to translate current research and field studies carried out by scientists into a format useful for the design practitioner in addressing site pollutants.

The book is divided into two parts. Chapters 1-3 of the book delve into the science and regulatory issues around phytotechnology, including the nature of particular site contaminants and field case studies. Chapters 4-6 focus on projecting the potential environmental, spatial, cultural and aesthetic qualities of these productive vegetation types matched to site programs and specific contaminates. In Chapter 4, 18 different phytotypologies (phytotechnology planting types) are developed. From Degradation Hedges to Multi-Mechanism Mats, pollutants are matched with productive planting types to mitigate those contaminants. In Chapter 5, opportunities for application of these phytotypologies on 16 different site programs (i.e. gas stations, road corridors, railway beds etc.) are highlighted. Aesthetic composition and consideration of natural and cultural systems are integrated with the potential phytotechnology role of plants to assist landscape architects, engineers and site owners.

The creation of productive landscapes is the ultimate objective; plantings that provide not only aesthetic functions, but enhance environmental and human-health conditions as well. With careful science-based research and planning, integrating this relatively new technology into design work can result in huge financial and environmental benefits. PHYTO bridges the critical science and engineering associated with phytotechnology and its effective design use in the field.

Excerpts from Book Reviews:
In two words: "Beyond comprehensive". Phyto is by far the most comprehensive compilation of Phytotechnologies out there. It truly goes beyond by tying together this broad set of plant technologies for cleaning the environment with the necessary form and functionality of landscape design. As an advocate and trainer in Phytotechnologies, I especially appreciate the illustrative graphics and easy-to-understand descriptions that clearly conveys the science, engineering, design, and planning to the technical and artisan alike. - David Tsao, Ph.D, BP Corporation North America, Inc.

Phyto is a hefty but approachable read. It’s clear and well organized, the language is scientific only when needed, illustrations are lively, charts and legends abound, and photos are interesting… Although the authors are never preachy, they show clearly the tragic extent of the harm humans have inflicted on the environment and future generations. But they also show how nature and constructed landscapes can beautifully regenerate themselves and thrive when they get what they need. – Laura Solano, ASLA, Landscape Architecture Magazine

This book is incredibly useful and an amazing resource for all practitioners. It is full of information that can be used to address the real issues that we face today and will face in the future. - Martha Schwartz, Principal of Marth Schwartz Partners

Phyto is a fantastic resource, not just to landscape architects but also to engineers and scientists as well. As Phytoremediation developed, advancement efforts focused on the biochemical science of the processes, and while the field was cognizant of ‘ancillary benefits’ valuation was not considered, mostly due to lacking knowledge and resources. Phyto brings the social and physical science into a common meeting place, and provides much needed discussion, fantastic visualizations and cross cultural presentation of plant-based technologies that can be incorporated into our urban spaces to serve both public health and the quality of life itself. - Joel G. Burken, Missouri University of Science and Technology

“It takes complex information and makes it comprehensible. It’s the kind of book you sit down with in a quiet room with a yellow highlighter. This is a practice area more and more important to landscape architects.”

- 2016 Awards Jury


Landscape Architects of Record:

  • Offshoots, Inc. & Harvard Graduate School of Design

Illustration Assistance:

  • Michael Lindquist
  • Andrew Hartness, ASLA
  • Harvard GSD Students