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Infill Landscape Codes

by Buck Abbey, ASLA, The Green Laws Organization, New Orleans, Louisiana

The Seattle Green Factor is a score-based code to increase the amount and quality of landscaping in new developments. Its basis is that well-designed landscapes benefit neighborhoods; reduce stormwater runoff; cool cities during heat waves; provide habitat for birds and beneficial insects; support adjacent businesses; and decrease crime. Landscape credits include green roofs, rain gardens, vegetated walls, trees and shrubs. Plants along the sidewalk, native plants and food gardens bring bonus credits. This is a preliminary design for the Plaza Roberto Maestas transit-oriented development on a vacant parking lot just north of Seattle's Beacon Hill Station.

"The Seattle Green Factor code establishes a weighted menu of landscape elements . . ."
----Diane Sugimura, DR 10-2011, City of Seattle 2011

Suburbanization Code
A well-planted city is where people desire to live. Think Boston, San Francisco, New Orleans, Charleston and Miami! However, the vast majority of landscape codes in this country were written for smaller cities and towns, not large cities.

The common landscape code makes heavy use of wide property line buffers, ample street yard plantings, parking lot screening and interior parking lot plantings. Suburban sites often have more available space, better possibility for shading with trees and larger parking lots. They also rely on artificial irrigation and parking lot detentions, both using underground piping.

Common landscape codes have been designed to convert raw land to suburban land. These land conversion codes could easily be called "suburbanization landscape codes."

Redeveloping tight inner city spaces cannot easily meet the more spacious technical standards created for suburban landscapes. They do not easily apply to big cities. A new kind of landscape code is needed for infill or redevelopment projects.

Big City Landscape Codes
The geography of development sites within large cities is complex. Inner city sites often have small lots, or may be composed of cobbled-together properties with irregular lot lines, intrusive utility systems and servitudes. Flag lots and even isolated parcels connected by servitudes are more common than most realize. Most inner city sites have excess paving, total site run off and irregular shade-sun patterns. Even circulation and approach can be trying, and security is a big concern in the middle of many cities. Add in large populations of pedestrians moving here and there and urban design becomes quite challenging.

A special kind of landscape code is needed. Big city landscape codes, which we might call "infill landscape codes," have not been completely defined, however, the last study of codes by the LSU Green Law Research Project of some of the larger cities in the United States offers good ideas about what an infill code should include.


The goals of the San Francisco Green Landscaping Ordinance are healthier, more plentiful plantings through screening, parking lot and street tree controls; increased permeability for front yards and parking lots; responsible water use through climate appropriate plantings; and improved screening by creating an ornamental fencing requirement, and requiring screening for newly defined vehicle use areas.

Urban Landscape Codes
Several of the cities studied have attempted to copy the common landscape code. This clearly does not work for urban areas. One must first understand and define the landscaping conditions of large cities and write appropriate design standards and technical requirement that are will work.

Second, the big city codes must recognize the open space landscape is not the back yard or undeveloped areas of a building sites, but the street, adjacent plazas and parks within an easy walk. Design components need to be related to the street, as well as behaviors and needs. This is best seen in the San Francisco Green Landscaping Ordinance and in the Seattle Green Factor Code. These cities acknowledge the street edge interface (public frontages), street tree landscaping, limited street garden landscaping, parking lot entry and screening. All of the codes reviewed place emphasize on street views, pedestrians, inter-lot connections, as well as the use of walls for screening, privacy and security. The Chicago and New York City codes do this very well. Certainly the view from above must be considered. Elements such as green arbors or green roofs are useful for casting shade, and screening ground level views of parking.

Thirdly, urban design complications implicit within a built up city mean designers need options rather than specific design standards as found in the suburbanization codes. It is difficult to write one set of design rules that apply in every urban situation.

Redevelopment landscape codes must have regulatory flexibility built in so the designer has options for the very complex conditions of cities, yet regulations must be written in such a manner that they are enforceable. The Dallas landscape code recognizes this fact by setting forth several options for designers. The Los Angeles code uses a flexible point system, while the Seattle code provides a point-based menu scorecard.

Lastly, big cities are embracing the idea of sustainability. Seattle and Los Angeles are doing this exceptionally well, followed by Miami and New Orleans. Collectively they promote soil improvements, use of native vegetation, water harvesting, reduction in the use of potable water, bioretention facilities, vegetative walls and permeable paving to encourage onsite storm water infiltration. Seattle provides bonus credit for green roofs, green walls and water harvesting techniques. Philadelphia is attempting to meet the standards of its Greenworks program.

Having a palette of options rather than specific standards make urban design easier to accomplish. Big city landscape codes are fundamentally different and must be directly connected to the open space system of the city. They must bring nature and ecology back to the city.

The codes mentioned herein have been annotated into a technical document. If readers have more interest, contact the author for a copy at, or call Abbey Associates Landscape Architecture at 225.766.0924.

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November 20, 2019, 3:09 pm PDT

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