Creating Non-Burn Zones Around Your Home: Learn Which Plants Burn Easily and Which Are Fire Resistant Plants
The Southwest seems to have five seasons now: spring, summer, fall, winter and unfortunately the fifth is coming up: fire season. For those of us who live in the mountains or foothills of not only the Southwest but throughout the western US, periodic and prolonged droughts have changed our lifestyle. It now requires a keen eye to keeping property trimmed and cleared.
Firescaping is a relatively new term in the field of landscaping. It means creating non-burn zones around your home. If a wildfire is coming through, it'll take what's in its path—including houses—unless there is no path for the fire to follow. The basic idea of firescaping is: the closer to your home, the less vegetation you want.
Ideally, there are three defensible zones that make up the principles of firescaping:
Zone One involves clearing a 30-foot area surrounding a house. Concrete or brick patios in this area are ideal as well as low growing perennials, annuals, groundcovers and irrigated lawns. If trees are to be planted in this first zone to provide shade, they need to be deciduous, as deciduous trees have higher moisture content in their leaves and don't contain flammable oils. Do not plant evergreen trees and shrubs such as pines, junipers and cedars. And it's best to cut down established evergreens close to the house. especially if there are branches overhanging the roof. Many broadleaf evergreens (Manzanita) and especially conifers (plants with needle-like leaves) are full of highly flammable oils that burst into flame with extreme heat. Also be sure to remove branches within 15 feet of chimneys and stovepipes.
Zone Two moves out another 70 feet, called the mid-zone. This area is for orchards and gardens. Lower limbs of trees should be pruned to 15 feet off the ground. On steep slopes groundcover plantings, especially succulent groundcover Sedum, Ruschia pulvinaris and Ice Plant (Delosperma) whose leaves are filled with water will retard the spread of a wildfire up a hill. Mowed lawns (Legacy® buffalo grass and Dog Tuff® grass), when green and actively growing, will also slow the spread of flames across the ground and up hillsides.
The basic idea of firescaping is: the closer to your home, the less vegetation you want.
Zone Three is no closer than 100 feet from the house. Trees need to be thinned so that crowns are separated by at least 10 feet. Prune branches up from the ground to a height of 10 feet. The goal is to keep a fire from "laddering" up from the ground. This is where brush underneath ignites lower branches that climb up a tree then jump to the crown or tree tops. When this happens, fires are out of control.
The basic idea of firescaping is: the closer to your home, the less vegetation you want. Create fuel breaks wherever possible with such items as pools, driveways and non-flammable fences. Lay rock, gravel, brick and paving in wide-open areas. Always use building materials with low flammability. For roofs in fire-prone areas, use tile, raised seam metal roof panels or flame resistant asphalt shingles. Never use wooden siding and cedar shingles as they are highly flammable and can be easily ignited by embers thrown up into the air by intense blazes.
And of course, keep propane tanks and fuel tanks well away from the house and outbuildings. And don't use a wood fence around fuel tanks to screen them from being visible from the house.
Specific plant recommendations for firescapes will vary greatly depending on the region where you live. The plant palette for coastal CA, OR and WA will be very different from colder, drier inland areas of the West and Southwest.
In general, deciduous trees and shrubs are much less flammable than broadleaf and needled evergreens (pines, spruces, junipers, fir etc.). In mild winter regions, Eucalyptus and Acacia are also to be avoided.
Avoid plants like large growing herbaceous ornamental grasses and other big growing perennials that die back to the ground in winter and leave a lot of combustible dried leaves and stems above ground. (If you do plant them, you must always cut them back to just above the ground in the fall.)