Fire resistant landscaping has become a hot topic for homeowners who live in the dry topography of Northern California, which can be a tinderbox in the hot summer and early fall months – our ‘fire season’. Fire danger is especially prevalent in hilly and wooded areas. Although there are plants listed as ‘fire retardant’ (see below), there are also several steps and precautions to be taken with respect to the location of plant material and maintaining a green belt around the property.
The concept of a ‘fire ladder’ is important, where fire in shrubs or limbs below the canopy can ‘climb the ladder’, so to speak, into the canopy and then spread from there. So lower limbs of flammable trees should be cut off regularly, and nothing should be planted below the canopy of trees.
A fire safe zone can be created, using stone walls, patios and roadways. Only fire-retardant plants should be planted within fifty to seventy-five feet of a home or structure. And large canopied trees should be planted far enough from a house so horizontal branches do not carry their foliage within ten feet of the structure.
It would also be useful, if possible, to install a separate irrigation valve with sprayers that can water the area surrounding a home in the event a fire is approaching.
Space is not only an important element in the garden aesthetically, but provides small buffer zones which make it more difficult for fire to travel horizontally, ‘jumping’ front plant to plant.
Most important, dry leaves should be raked and dry grass should be closely mown within one hundred feet of a home. This is the ‘kindling’ that can easily catch fire.
Fire-retardant trees:
California pepper (Schinus molle) – fast growing evergreen 25-40 ft. tall and wide
African sumac (Rhus lancea) – slow growing evergreen 20-30 ft. tall and wide
Bottlebrush (Callistemon) – fast growing evergreen, many varieties available
Carob tree (Ceratonia siliqua) – fast growing drought tolerant, hardy evergreen 30-40 ft. tall and wide
Fire-retardant plants:
Yarrow (Achillea) – full sun perennial, many varieties and colors available
Ice plant (several) – many varieties of low growing succulent perennials
Potato vine (Solanum jasminoides) – vigorous twining vine to 30 ft. long
Nerium oleander – full sun, drought tolerant evergreen, to 20 ft. tall and 12 ft. wide
Holly-leafed cherry (Prunus ilicifolia) – full sun evergreen to 25 ft. tall
Rosemary (Rosmarinus officinalis prostrata) – tough hardy, drought tolerant full sun evergreen, great on slopes, many varieties
Cape honeysuckle (Tecomaria capensis) – full sun evergreen vine or shrub
Verbena (several) – full sun ground cover perennial
Wisteria – full sun deciduous vine, several varieties
Rockrose (Cistus) – full sun evergreen sun, many varieties, colors and sizes
Fire resistant landscaping is great in California because the plants are often drought tolerant also. Two plants listed above, rosemary and rockrose, are not only fire-retardant but also deer resistant and helpful with erosion control. Perfect for dry rocky hillside areas where deer are prevalent !
Also make sure that there is easy fire department access for their trucks. Streets and driveways should be wide enough for fire trucks, and plants and trees that encroach upon these areas should be regularly cut back, if not completely removed.