Fire-smart shrub pruning: Reducing fire risk in your garden

As a UC Master Gardener, I've been working to make our landscape more fire-smart. Each year, we trim tree branches away from the house. Last summer, we removed plants within five feet of our home and replaced them with gravel to create what firefighters call Zone Zero. We've also spaced plants farther apart and removed what are known as fire ladders, layers of vegetation such as shrubs, small trees or dry branches that allow flames to climb from the ground into the tree canopy. When that happens, a surface fire can quickly become a fast-moving crown fire. There's another step gardeners can take: fire-smart pruning of shrubs. Many common landscape shrubs collect dead wood inside the plant over time. When you look inside plants such as Chinese fringe flower, Loropetalum; lavender, Lavandula; or escallonia "Apple Blossom," you may see dry branches and twigs hidden in the interior. That dry material can become fuel during a fire. One reason this happens is the way shrubs are often pruned. Landscape crews sometimes shear shrubs into tight round shapes using hedge trimmers. While this creates a neat appearance, it also blocks sunlight from reaching the interior of the plant. Without light and airflow, dead material builds up inside the shrub. A better approach is to prune shrubs into their natural form. Instead of shearing the outer shell, selectively remove branches from within the plant. This allows sunlight and air to reach the center and reduces the amount of dry material that can accumulate. When pruning shrubs for fire safety, focus on a few simple goals: Remove dead material: Look for dry branches, twigs and leaves inside the plant and prune them out. Open up the structure: Thin some interior branches so the plant is less dense and air can move through it. Maintain good spacing: Shrubs should not grow tightly against one another. A good rule is to keep space between shrubs equal to at least twice the height of the plant. This is for level ground. It's four times this for a 20-40 percent slope and six times for more than a 40 percent slope. Spacing helps prevent fire from spreading easily from one plant to the next. Avoid ladder fuels: If shrubs are growing under trees, maintain vertical space between them. Ideally, there should be 10 feet or three times the height of the shrub between the shrub and the lowest tree branch so fire cannot easily move upward. Fire-smart pruning also helps plants stay healthier. Light and airflow reduce disease, encourage stronger growth and make shrubs easier to maintain over time. Many of these pruning tasks can be done by homeowners, or you can ask your landscape service to prune shrubs using these fire-smart principles rather than simply shearing them. In wildfire-prone regions like ours, small actions in the garden can make a difference. Removing dead material, opening up dense shrubs and maintaining good plant spacing all help reduce the fuel that allows fire to spread. Fire-smart landscaping is not about removing every plant. It's about managing plants wisely so they are less likely to carry fire toward your home.