Defensible Space

Wildfire is a year-round threat in Napa County. Defensible space is one of the most important steps you can take to protect your home — and your neighbors — from wildfire. Your defensible space slows fire spread, reduces ember ignition, and provides firefighters a safer place to defend your property. Creating defensible space doesn’t mean clearing everything; it means making smart choices about placement, spacing, and maintenance.

Defensible Space Zones

Illustration of a house surrounded by three colored rings labeled Zone 0, Zone 1, and Zone 2, showing a zoning layout radiating outward from the home.

 

Zone 0 (0-5 feet): Ember-Resistant Zone

Most homes are lost to wildfire when windblown embers ignite something right next to the house. This zone is your most critical defense.

What to Do:

  • Remove dead plants, leaves, needles, and debris from roofs, gutters, decks, and stairs.
  • Keep the first 5 feet around your home clear of combustibles like firewood, lumber, garbage bins, outdoor furniture, or planters.
  • Replace bark, wood, or rubber mulch with rock, gravel, or hardscape.
  • Trim tree branches within 10 feet of chimneys and at least 5 feet away from roofs and siding.
  • Mature, healthy oaks, redwoods, or shade trees can stay — embers ignite fuels on the ground, not in living canopies.

Zone 1 (5-30 feet): The Home Protection Zone

Fires in our canyons and hills can spread fast. This zone should slow flames and prevent direct fire spread to your home, while also conserving water and supporting native plants.

What to Do:

  • Maintain plants — keep them green and pruned; remove dead or unhealthy material.
  • Space it out — separate shrubs, trees, and structures so fire can’t jump between them.
  • Prune trees — remove lower branches (6–10 feet up for tall trees, bottom third for smaller ones).
  • Maintain at least 10 feet between tree canopies and homes, sheds, or decks.
  • Use hardscape — granite paths, stone walls, or dry creek beds can act as fuel breaks between plantings.
  • Choose wisely — favor California natives like manzanita, toyon, or ceanothus; avoid flammable ornamentals such as Italian cypress.
  • Mulch smart — use composted wood chips (2–4 inches deep); avoid rubber or plastic mulches.
  • Groundcovers — keep lawns or groundcovers irrigated and under 6 inches tall.

 

Zone 2 (30-100 feet): The Reduced Fuel Zone

On steep slopes and ridgelines, fire gains speed and intensity. In rural areas of Napa County, Zone 2 often overlaps with neighbors’ vineyards or open land — coordinated efforts here protect entire communities.

What to Do:

  • Cut or mow annual grasses to 4 inches or less.
  • Maintain horizontal spacing between trees and shrubs, and vertical spacing between grasses, shrubs, and tree canopies.
  • Remove fallen leaves, needles, bark, and small branches if deeper than 3 inches.
  • Maintain a 10-foot bare soil ring around stacked woodpiles.
  • Around outbuildings and propane tanks: clear 10 feet of bare soil in all directions plus another 10 feet with no flammable vegetation.
  • Avoid stripping land to bare dirt — Napa’s hillsides are prone to erosion and mudslides if vegetation is completely removed.

Firewise Landscaping

Defensible space doesn’t mean stripping your yard bare. With thoughtful planning, you can have a landscape that is beautiful, climate-appropriate, water-wise, and fire-resilient. The plants you choose and how you maintain them can make all the difference.

Principles of Firewise Landscaping

  • Maintenance matters most — all plants will burn if neglected. Regular watering, pruning, and clearing dead material are more important than plant choice.
  • Group, don’t mass — plant in small clusters with open space or hardscape between, rather than large continuous beds of shrubs.
  • Layer for safety — low groundcovers, then shrubs, then trees, with vertical spacing so fire can’t “ladder” upward.
  • Use hardscape creatively — rock mulch, gravel paths, patios, and dry creek beds break up fuels and double as attractive design elements.
  • Irrigate wisely — drip irrigation conserves water and keeps plants healthy, especially critical in Napa’s hot, dry summers.

Better Plant Choices

When selecting landscaping plants:

  • Favor California natives that are drought-tolerant and low-resin (e.g., ceanothus, toyon, manzanita, native sages).
  • Choose broadleaf evergreens and deciduous trees rather than conifers, which ignite more easily.
  • Pick shrubs with supple, high-moisture leaves (e.g., coffeeberry, bush anemone).
  • Use irrigated low groundcovers (e.g., yarrow, creeping thyme) to replace flammable grasses.

Plants to Avoid

When selecting landscaping plants, avoid:

  • Highly flammable ornamentals such as Italian cypress, juniper, or pampas grass.
  • Plants that produce oily or resinous litter (eucalyptus, pine, cedar).
  • Invasive species that spread aggressively and create hazardous fuel loads (arundo, scotch broom).

Mulch Guidance

  • Use composted wood chips (2–4 inches) for water conservation and weed suppression.
  • Avoid bark nuggets, shredded redwood, or rubber mulch — all ignite easily and burn intensely.
  • Around the first 5 feet of your home, stick to rock or gravel only.