Research in Landscape Architecture

Posted by on Sep 1, 2015 | 0 comments

How do we know what we know? Do oyster reefs really protect against storm surges? Are floating wetlands really all that great? What about biochar or hugelkultur? What plants can be used for phytoremediation?

This post is in part a response to Amy N’s recent post on the complexities of urban cleanup but also contains material I’ve been ruminating about all summer. This summer, I have been interning for the Landscape Architecture Foundation (LAF) here in DC. LAF puts out the Landscape Performance Series website (, which includes landscape “fast facts” derived from published research, case studies of sustainable projects, and benefits calculators. It’s a good resource to check out! I’ve been mostly involved with reading published, peer-reviewed research and adding to the “fast facts” section, along with editing the forthcoming guidebook and doing graphic design and general office tasks.

Landscape architecture is a profession on the edge of art and science, and historically there has been tension between the two factions. Research has not been very important in the profession, which makes sense for an art-based profession but not a science-based one. As landscape architecture plays a larger role in ecosystems and infrastructure, it makes sense for the profession to generate its own knowledge about methods and best practices and use evidence-based design.

To take a look at another profession, doctors rely on research to help them make medical decisions every day. Landscape architecture is at a stage analogous to the “leech” phase of medicine. We propose fixes and build projects but do we know they will work? We don’t always monitor and study built projects but move on and create more, still without knowing if they produce the desired results. It is very difficult for most practicing landscape architects to do research on top of running a business, thus we need a strong research arm in the profession, and we need to know how to access the significant body of research that already exists.

So, what’s the best way to find existing research?

  • Google Scholar is accessible to everyone. While it’s not the *best* search engine for scholarly journals, it’s open to the public while others (Web of Science, for example) require university access. You can really just type in “treatment wetlands” or “street design safety” and see what you get.
  • Research is *much* easier if you have access to a university library that subscribes to scholarly journals. Otherwise you’ll likely just have access to the abstract, which usually shares the paper’s conclusions but not methods.

Things to note when looking up scholarly articles:

  • These articles are written in technical scholar-speak and can be a huge pain to read!
  • Just because you find one article saying, for example, that trees reduce air pollution doesn’t mean that there aren’t 10 more articles saying trees have no effect on air pollution. Scientific articles can contradict each other. If you’re looking for a good overview on a topic, try to find a recent review paper that looks at a lot of different articles and summarizes them.
  • Each paper must contribute something new to the field, and usually the aggregation of knowledge is slow (each paper contributes a tiny amount or slightly different angle).
  • If you can sort by number of citations, that will help you find the foundational (but not necessarily most recent) contributions to the field. Google Scholar doesn’t let you do this.
  • If you find a good paper, check out their sources to see what papers they’ve cited.

Luckily, as a landscape architect you don’t have to write these papers and you can usually assume that since they are published, they are at least passable papers!


Phragmites australis

Photo: by Andreas Trepte (Own work) [CC BY-SA 2.5 (], via Wikimedia Commons

Amy N. was trying to find articles about native plants in phytoremediation, and she asks some great questions (potentially great Master’s/PhD thesis questions if they haven’t been answered…) Finding articles on native plants in phytoremediation is a bit tricky. It is very easy to find scholarly articles with “phytoremediation” in the title, but these articles come from all over the world and native plants of course vary by location.

I don’t have time right now to search through every article on “phytoremediation wetlands”, but here are a few highly-cited ones:

  • Phragmites australis, an invasive species in the northeast U.S. sequesters more metals belowground than the native Spartina alterniflora, which also releases more via leaf excretion (Weis, 2004))
  • Four wetland plant species (Scirpus validus, Carex lacustris, Phalaris arundinacea, and Typha latifolia) were grown in monoculture and as a four-species mixture to compare effectiveness of nutrient removal in controlled… outdoor subsurface treatment wetland microcosms. S. validus was most effective and P. arundinacea was generally least effective at reducing N and P in monocultures, with treatment capabilities similar to unvegetated microcosms. The four-species mixture was generally highly effective at nutrient removal, however the results were not significantly different from the monocultures (Fraser, 2004).

Scholars spend a significant amount of time reading all the articles they can find on a specific topic in order to form a basis of knowledge and to keep up on new developments, which is pretty hard to do as a working person. Luckily for us, two landscape architects have already written a big book on phytoremediation. I just got “Phyto: Principles and Resources for Site Remediation and Landscape Design” by Kennen and Kirkwood (2015) out through interlibrary loan from my university. So far, it’s a good, realistic look at phytoremediation. It’s not a silver bullet, they say, and they carefully outline its limitations. The book doesn’t cover remediation through wetlands, as that topic has been covered elsewhere, but it would be a very useful reference for anyone doing projects that involve phytoremedation.

Have at it, researchers!

… and stay tuned for a critique of Oyster-techure and a report on the ability of oyster reefs to mitigate storm surges (if I have time…)

– Renee


Fraser, L. H., Carty, S. M., & Steer, D. (2004). A test of four plant species to reduce total nitrogen and total phosphorus from soil leachate in subsurface wetland microcosms. Bioresource technology, 94(2), 185-192.

Weis, J. S., & Weis, P. (2004). Metal uptake, transport and release by wetland plants: implications for phytoremediation and restoration. Environment international, 30(5), 685-700.


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