Garden Basics: Zones and Double Duty Plants

Last month I discussed WaterWise and Firescaping audits. This article will cover what zeriscape and defensive space zones are and the plants that are both WaterWise and Firescape smart.

First let's discuss zones. In zeriscape there are three zones.

Zone 1 is the place closest to the house and is the mini oasis in your landscape. Potted plants, a small lawn or water feature, and thirstier plants are typical in this area.

Zone 2 consists of low water use plants that would only need an occasional deep watering during the hot, dry months. This is a good area to use contouring techniques such as berms to catch rainwater or installing a drip irrigation system.

Zone 3 is a transitional area, where plants that require little or no supplemental irrigation are used. If you have any natural vegetation and plants in this area on your property-keep it. Since this is the zone furthermost from the house and preferably least visited, the emphasis here is to use plants that can survive on rainfall alone.

In Firescaping there are four zones.

The first is The Home Zone, 0 to 6 feet. The goal is to prevent the spread of fire from the structure to vegetation or vegetation to structure. It is recommended that all fuel sources from this zone be removed. The objective is to land scape this zone with gravel, concrete, or left bare. Using less flammable plants, small lawns, and flower beds are good choices if they are kept well watered.

The Yard Zone, 6 to 30 feet. The goal is to prevent a fire from moving from ground fuels to brush or tree crowns and to slow the rate of fire spread. The objective is to eliminate fuel ladders, limit litter layers to three inches or less, removing dead materials off the ground and from plants, and pruning branches of trees to at least 10-15 feet above the ground.

The Brush and Screen Zone, 30 to 75 feet. The goal is to keep a wildland fire on the ground to minimize intense burning and damage to overstory vegetation. It is the primary zone for fire suppression. The objectives are the same as the yard zone.

And finally there is The Woodland/Forest Zone, 75 to 100 feet. The goal is to provide a space where a fire will "cool down, slow down, and stay on the ground" to maintain fire safety. Objectives are the same as the yard zone to include creating patchy landscaping, thinning trees to 20 feet trunk spacing, and remember that the fuel reduction zones increase for properties on ridges and slopes.

As for plants, any succulent plant such as ice plant, sedums, sempervivums, portulaca, prickly pear, barrel and hedgehog cactus are highly recommended for use in the home zone, being the most fire resistant plants for firescaping. Other WaterWise/Firescape wise plants include desert marigold, globemallow, penstemon, desert willow, daleas, salvias, and the Atriplex species, particularly four wing saltbush, which is very fire resistant. There are dozens more plants on both lists - too numerous to list here so I've listed my favorites!

Now for the "Risky Business"- these are the plants that are very volatile and should be avoided, if possible, in the home and yard zone for firescaping: Acacia, Cedar, Cyprus, Eucalyptus, Juniper, ornamental grasses, Pines, Carolina Jessamine, Bougainvillea, and berry vines.

Special Thanks to Cado Daily and Mary Dalton for providing source information. To receive an audit contact Cado Daily, The University of Arizona Cooperative Extension, Water Conservation Educator, WaterWise Program, at 458-8278 ext. 141. Mary Dalton, Fire Prevention Technician, Sierra Vista Ranger District, Coronado National Forest, can be reached at 378-0311. Visit the Home Fire Protection website at

Cheri Melton
May, 1998