Articles by Owen Dell

LANDSCAPING IN HIGH FIRE HAZARD AREAS by Owen E. Dell (written for Southern California)

We live in what's called the CHAPARRAL-URBAN INTERFACE. It's literally the most flammable place on earth. Our safety and the security of our homes depends on the proper management of planted and natural vegetation to reduce fire hazard to a reasonable level. Here are some things you can do to reduce the risk of uncontrolled wildfire on your property.

By reducing the amount of vegetation around your home, you make it easier for firefighters to protect your property. Thin native vegetation, allowing individual plants to remain in clumps that are separated from each other by at least 20 ft. Reduce flammable vegetation around the house. Cut back tree branches that hang over the roof. Keep shrubs and trees trimmed to remove low-hanging branches and deadwood. Cut down weeds.

Use non-flammable building materials like stone, brick, adobe and concrete. Avoid flammable wood structures in the garden. Wood decks hanging over unkempt vegetation are the worst offender. Decks and other wood structures must be built to resist fire in high fire hazard areas; check with your local building department. Cover decks with approved fire resistant skirting or use concrete or stone patios instead. Flammable wood fences can act as fuses in a fire; use chain link fences or masonry walls instead. Avoid using flammable mulches like bark or wood chips near the house; use gravel, crushed rock or decomposed granite instead.

Some plants are more flammable than others. Conifers like pine, cypress, cedar and juniper are the worst offenders. Other very flammable plants include Bougainvillea, pampas grass, Eucalyptus, New Zealand flax, chamise and many grasses. Any plant will burn, but plants with lots of water stored in their leaves, or which contain large quantities of salts, are more resistant to fire. Examples are succulents, Oleander, Myoporum, lawns and many low-growing ground covers.

The way plants are arranged in the landscape is more important than the kind of plants you use. The ZONE SYSTEM uses four bands of plantings to slow an approaching fire and create defensible space.

ZONE FOUR, the outermost zone, consists of thinned native vegetation with free-standing clumps of pruned shrubs and low-growing plants or mulch in the remaining open space. ZONE THREE, closer to the house, is low plants to 2 feet tall that burn very quickly and offer very little fuel to the fire.


ZONE TWO is a greenbelt of succulents and very low-growing vegetation that is reluctant to burn. ZONE ONE, the plantings near the house, consists of less flammable species that present a minimal risk of exploding into flames during a wildfire.

For a look at the zone system in action, visit the FIRESCAPE DEMONSTRATION GARDEN in Santa Barbara at Stanwood Drive and Mission Ridge Road.

Avoid removing too much vegetation, especially on steep slopes or unstable ground. The loss of foliage cover above ground and roots underground can result in surface erosion and massive slope failures. If you're not sure how to proceed, check with a professional first.

Select plant species that are suitable for erosion control on slopes. Use erosion control netting or other mechanical means of temporary protection until plants mature. Control the flow of water, keeping it away from slopes and channeling it to safe collection points. Maintain drainage systems in proper working condition. Control gophers; their tunnels can contribute to slope failures.

Use a combination of drip and overhead irrigation to keep plants healthy and supplied with moisture. Avoid over-watering, especially with native plants, but don't let plants become drought-stressed.

You need to maintain your landscaping to keep it fire safe. Remove weeds annually. Keep plants pruned and groomed, with a minimum of dead twigs and branches. Rake up leaf litter and put it on the compost pile. Keep things watered. Remove leaves and litter from the roof. Don't allow piles of brush and rubbish to build up. Keep the ground covered with appropriate plantings or mulches to prevent erosion.

The other vulnerable element on your property is your roof. Replace wood shingle or other flammable roofs with a "Class A" roofing material. Also, avoid flammable wood siding and decks overhanging hillsides. Open eaves also invite trouble; boxed in eaves are better. Avoid large window openings on the "fire side" of the house. Finally, be sure the vents in the eaves and attic are screened to keep out flying embers.

Other Articles by Owen E. Dell