Landscaping Ordinance Model and Commentary

The landscaping ordinance contains the development standards for how much, what type, and the location and design of landscaping on a site. Although perhaps not the most intuitive connection to hazard mitigation, the landscaping ordinance presents several opportunities for reducing risk to flood, drought, geologic hazards, wildfire, and extreme heat. This model code and commentary describes how certain elements of a landscaping ordinance may reduce risk, and provides sample language for consideration.

The following sections provide example language for each of the common elements. Model language is in blue shading. Commentary is located in italics in the column at the right. The model language used in this document is based on existing ordinances from communities around the state and nation. The language is illustrative only; consult local counsel to tailor language for your jurisdiction.

Limiting the amount of parking required is possibly the most effective way to reduce impervious surface in parking areas; however, that reduction is achieved in the parking regulations and not in the landscaping ordinance. Parking lot landscaping is often addressed as a separate section within the landscaping ordinance.

Communities vary in terms of the degree of design within parking areas. Variables include how much landscaping is required; whether or not landscaped islands are required; how stormwater is treated within a parking area; and whether or not additional perimeter landscaping is required.

Thoughtful considerations for the types of landscaping (species/materials), and the amount of landscaping required in parking areas can help reduce the impacts during a flooding event and can help conserve water in times of drought. Additionally, any reduction in the amount of impervious area in a parking lot will reduce the heat island effect, especially during periods of extreme heat.

Some communities require certain stormwater management improvements in parking areas. For example, the Town of Carbondale requires landscaped islands or rain gardens as part of the parking area design standards. The model language below is based on that example.

For many snow-prone mountain communities in Colorado, the issue of snow storage is important. An effective approach to addressing snow storage is to ensure adequate set-asides for snow storage adjacent to paved areas are provided, while also protecting landscaped areas. Some model language for snow storage standards most relevant to the landscaping ordinance is provided below, based on Summit County’s standards:

This section addresses the types of planting materials allowed and the number of plant units required.

For hazard mitigation purposes, the type and amount of landscaping is important. For flooding, landscaping can determine how the site performs when flooded, and how much water can be conveyed and/or detained on site. For wildfire, some types of landscaping materials are more flammable than others, and the amount of vegetation equates to the amount of potential fuel. For drought and extreme heat, some species are more tolerant to periods of drought or extreme temperatures and require less water. Certain species may also be more prone to becoming projectiles during extreme wind or tornadoes.

Native species are the most suitable, and many communities maintain a list of appropriate native species. Native species can survive under normal climatic conditions, and are therefore more water-efficient. See the model language below, tailored from an example in Sedona, Arizona:

Communities also vary in how they regulate the number of plants and/or trees. There can be differentiations based on use type (e.g., different for golf courses vs. single-family residential vs. shopping centers), different standards for private yards vs. treelawns, and exceptions allowed for urban environments.

Many landscaping ordinances also include standards for reducing the amount of high-water usage landscaping. Water-efficient landscaping materials help communities conserve water without sacrificing other objectives such as aesthetics and/or flood control. Some communities regulate the amount of native plants required – to avoid species that may require a lot of water. Other communities provide a list of specific water-efficient plants that are appropriate or refer to a regional- or state-approved plant species list.

Some communities place a maximum limit on the amount of turf grass used for new developments, and in more complex scenarios have separate watering rates depending on the amount of turf grass. Communities should consider the applicability of such limitations. For example, consider whether turf grass limitations will apply to single-family or duplex dwelling uses beyond those associated with a new subdivision.

Low-impact development standards help reduce stormwater runoff and improve water quality through the use of natural on-site features (green infrastructure), in-lieu of conveying and/or storing water in piped infrastructure. These systems help reduce risk to natural hazards by improving permeability, and thus preventing conveyance during flood conditions (with an added benefit of improving water quality), help conserve water through the use of water-efficient plantings, and reduce the heat island effect by replacing hardscape with natural systems.

Communities can emphasize the importance of green infrastructure by providing descriptions of low-impact development (LID) options and including incentives, such as reduced parking requirements.

See the Stormwater Ordinance model code language for more.