Developing a Firewise Garden in the Wildland Urban Interface by Matthew Solano

Lookout Mountain Nature Center
All photos: Matthew Solano

Over the last few months development has begun on a new Firewise demonstration garden at the Lookout Mountain Nature Center (LMNC.)  The areas to be developed are adjacent to the south and east sides of the LMNC building and consist of three zones: a part-sun area and two full sun areas. Hazard zone site assessment, defensible space and ignition resistance were key determinants in the design and plant selection for this garden. This project has been a team effort with Quinn Wicken and Patti O’Neal.

During my career as a volunteer firefighter, I have seen firsthand how hardening homes (e.g., fire resistant roofs, siding, decks, etc.) can increase the likelihood that a home will survive a WUI fire.  Equally important was the extent to which homeowners provided defensible space near their home by thinning trees and other vegetation on their property.  As gardeners and landscapers, these efforts can be significantly enhanced by careful consideration of what plants are planted in hazard zones. In general, the planting of ignition resistant plants and maintenance of landscaped areas are key components to helping emergency responders save homes during WUI fires. Developing a Firewise demonstration garden provides an ideal opportunity for WUI homeowners to see how low-ignition plants can be incorporated into their landscape.

Site Assessment 

Initial steps to incorporate principles of Firewise defensible space included close examination of the building adjacent to the demonstration garden to identify measures needed to reduce or remove existing flammable plant materials within five feet of the building sides.  The building itself is sided with non-flammable stucco and wall rock material which were strong factors in determining if any existing plants within this zone present a hazard.  While pruning and shovel pruning of some plants will be required, the building is bordered by a 5-10 foot wide gravel path which is a major factor in reducing the probability of conflagration in the ember hazard zone closest to the building.

In addition, the site was assessed to determine the ambient sunlight and naturally available moisture in each microclimate.  This process was informed by noting the existing native plants inhabiting areas immediately adjacent to the site.  For example, sun-loving and drought tolerant Solidage misouriensis (Missouri goldenrod,) Heterotheca fulcrata (false golden aster,) and Artemisia lanulosa (Louisiana sage) were growing well in areas several feet from the building. Less drought tolerant and shade tolerant Achillea lanulosa (wooly yarrow,) Oenethera elata (tall evening primrose) and Mondara fistulas (horsemint) were growing in cooler areas with less light and closer to the drip line of the building.  Existing Ribes spp. (currant,) Yucca glauca (soapweed yucca,) and Chrysothamnus spp. (rabbitbrush) bushes were located within the area to be developed and will be an important component of the demonstration garden. Almost all of these plants are listed in the CSU Extension Fact Sheet entitled Fire-Resistant Landscaping 6.303 located here: https://extension.colostate.edu/topic-areas/natural-resources/fire-resistant-landscaping-6-303/.

Initial Site Preparation

This summer all three areas of the demonstration garden were prepared by removal of existing undesirable plants for example native grasses and annual weeds from all areas and solarization of the full sun area of the garden.  Native plants that will likely be incorporated into a new garden design were not removed.

Plant Selection

In determining which plants would be used in the demonstration garden three critical criteria were used: All plants must have all three of these:

•   Have low-ignition/fire-resistant traits (per CSU Extension Fact Sheet entitled Fire-Resistant Landscaping - 6.303)

•  Meet ‘right-plant/right-place’ criteria including survivability above 7,500’ elevation

•  Whether a Colorado native and non-native plant, it must have low-water and low maintenance requirements. 

 Additional favorability factors include resistance to deer and rabbit grazing, seasonal bloom periods, color, foliage type and mature size. 

 Next Steps

Current plans to complete the installation of the Firewise Demonstration Garden include improving hardscapes in the area, planting selected native and non-native plants and placement of non-flammable mulches within all areas within five feet of the building.   It will be a busy spring, but we hope to be open for visitors in early May, 2022.