Fire Safe Landscaping

From UCANR Marin and Sanoma County “Fire Safe Planting”

The short version of the story is this: There are very few plants that are “fire safe”. Most plants have some woody structure, and wood burns. There is such a thing as fire-safe landscaping.

Fire safe landscaping is primarily a function of how the landscape is designed, and how it is maintained. Plant species selection is a relatively minor component.

There are some plants that are basically made to burn: they are adapted to environments where fires are routine, and they depend on these fires for regeneration and reducing competition from other plants.  They do this by burning fiercely when ignited, and generally ignite easily.  Greasewood, chemise, knobcone pine, and some eucalyptus species are all good examples of this.  These plants should generally not be part of a landscape plan that includes fire safety.

There are a few plants that are “fire safe”.  However, not everyone is willing to live in a landscape populated solely with Aloe vera, chard, and snapdragons.  And even plants that we routinely think of as “fire safe” can burn if not cared for properly.  Even iceplant.

In some instances, a “fire safe plant list” may give property owners a false sense of security.  Homeowners who believe that their properties are “fire safe” due to the species they’ve selected may be less worried about maintaining their landscapes.  Why worry, right?  Every plant on the property is from a “fire safe” plant list!

Most of us are familiar with the coast live oak.  The species is almost as associated with California as the redwood tree.  Most fire-safe plant lists list coast live oak as fire safe.  And yet a neglected coast live oak, with lots of interior deadwood and a canopy that grows all the way to the ground, can be a giant torch waiting to ignite.  That same tree CAN be very fire safe if it has adequate access to water, has a canopy trimmed up off of the ground, and has few dead twigs in the canopy.  Maintenance and design, not species selection, is the key.

For more information on designing fire-safe landscapes, please see Home Landscaping for Fire

Other helpful information:

Post Fire Restoration – “Do’s and Dont’s

Soil Quality Resource Concern-Hydrophobicity

 

Lessons learned from the most recent fires in the Ojai Valley:  All plants can burn given the right conditions of excessive wind,  heat, exposure, lack of rainfall etc.   Oak trees that have have not been maintained and cleared of  dead branches are more fire prone so the key is maintenance and placement.

To protect your home, creating defensible space around your home is a must during fire season. There are many things you can do.  Here is a list, not in order of priority.
1.  Installing metals screens on vents to keep embers out. More info on installation of vents here.

2. Care should be taken to not place fire prone plants adjacent to any structures and preferably not within 30 feet of the house. Info on plants that are highly flammable is here.  FIRE SAFE Landscapes and Plant LISTS –
FIREWISE PLANT List Info from San Diego
DESIRABLE PLANT LIST FOR HIGH FIRE HAZARD AREAS – Santa Barbara

From California Native Plant Society Fire Recovery Guide https://www.cnps.org/wp-content/uploads/2018/04/CNPS-fire-recovery-guide-LR-040618.pdf

What are the best plants to use in replanting areas damaged by fire?
A fire resistant landscape approach maintains a 100’ defensible space around homes by removing combustible materials and having hardscape features with high moisture/low flammability plants to limit potential fire fuels. Careful spacing with low-growing native, drought-tolerant plants is best to resist fire, although no plant is fireproof. Keep plants from creating a fire ladder up trees and select trees with low sap or resin (such as hardwoods like our lovely oaks) instead of highly flammable
pines and eucalyptus.

3. Remove highly flammable plants:  examples of include ornamental juniper, Italian cypress, Leyland cypress, rosemary, arborvitae, eucalyptus, and some ornamental grasses.   Remove “high fire hazard”  plants. I still see Mexican feather grass around town, with very dry and brittle. The slightest wind sends the delicate flower heads and thin leaves of this perennial grass into motion. It is very flammable and invasive.   See CAL INVASIVE PLANTS COUNCIL and look for the high risk plants (some are still sold in nurseries)

Also see Santa Barbara High Fire Hazard Area Landscape Requirements in City of Santa Barbara, Fire Prevention Bureau,  Ordinance #5779

https://www.santabarbaraca.gov/civicax/filebank/blobdload.aspx?BlobID=16482

Plants to AVOID

4.   Mulch, Mulch, Mulch!

Up to 70% of water can evaporate from the soil on a hot day if you don’t have mulch as a protective layer on top.  Mulch is one of the best moisture holding strategies you can employ.  It prevents evaporation from the soil surface, helps suppress water-thieving weeds from growing and many mulches add vital nutrients to the soil at the same time.

Avoid fine mulches that tend to clump and become water-repellent.  Instead, use a coarser mulch which allows water/rain to move down through to the soil.  A depth of 8-10cm in a garden bed is ideal.  Apply mulch onto moist soil and water in well.

During Santa Ana wind and fire season, understand the combustability of various types of mulch with composted wood chips the best. https://firesafemendocino.org/wp-content/uploads/2014/05/The-Combustability-of-Landscape-Mulches.pdf

5. See resources of the state and local Fire Safe Councils to understand how to create defensible space on your property.  FSC are volunteer organizations committed to improving local fire safety through preparedness and homeowner education and training. Find our local Council website link below:
California Fire Safe Council | Mobilizing Californians to protect their …
Ojai Valley Fire Safe Council
Central Ventura County Fire Safe Council
Mendocino Fire Safe Council

6. Install a roof top irrigation system to water down roof tops.  Very effective when irrigation is set on a timer to run off a dedicated rain tank.  More info on how they do it in Canada http://www.onestopfire.com/sprinklers.htm

7.  Install rain gardens and rain tanks to capture roof runoff.

8. Landscape Design Templates- Free, Easy-to-Permit Landscape Design Templates for the Fire Rebuild from Sonoma-Marin Partnership http://www.savingwaterpartnership.org/concept-plans-and-design-templates/

Articles

LA TIMES Forget curb appeal — when it comes to fire-safe landscaping, think embers, meadows and ‘defensible space’

Links:
California Native Plant Society Fire Recovery Guide https://www.cnps.org/wp-content/uploads/2018/04/CNPS-fire-recovery-guide-LR-040618.pdf
AG & Natural Resources
Home Landscaping for Fire http://cemarin.ucanr.edu/files/30726.pdf
Climate, Fire, and Habitat in Southern California https://ucanr.edu/sites/SAFELandscapes/Fire_in_Southern_California_Ecosystems/
Southern California Guidebook to S.A.F.E. Landscapes https://ucanr.edu/sites/SAFELandscapes/files/79452.pdf
Home Survival in Wildfire Prone-Areas:  Building Materials and Design Considerations https://anrcatalog.ucanr.edu/pdf/8393.pdf