Portland is for nature lovers, but Mother Nature can turn on a dime. If you’ve been thinking about how you can protect your landscape from wildfires, there’s no better time than now.
Follow these tips to protect your home against Mother Nature’s fury.
- Prepare your home ignition zone
- Use fire-resistant plants
- Maintain plant spacing
- Keep fencing and decks fire-safe
- Use hardscaping
Note: Experts recommend that homeowners focus on the house first and then move to the landscaping. After you’ve prepared your home, come along with us as we discuss helpful ideas on how to prepare your landscaping.
1. Prepare your home ignition zone
Preparing your home ignition zone is key to reducing the chances for your home to ignite. The home ignition zone (HIZ) includes the house and the 100-foot radius surrounding it.
The HIZ is divided into three subzones: the immediate zone, the intermediate zone, and the extended zone. The HIZ is sometimes called the “defensible space” around your home.
Immediate Zone (0-5 feet from the home, porch, or other outdoor structures)
If you are feeling overwhelmed by the idea of preparing your landscape for a wildfire, start here.
The goal in this zone is to create a non-combustible area 5 feet around the perimeter of your home and deck. The goal is to have any embers die off and not ignite anything close to the house. It is also called the “ember-resistant zone.”
Here’s how to prepare the immediate zone around your home:
- Nix the mulch. This may sound harsh, but save the bark mulch for the intermediate and extended zones. Remember, mulch burns, and you don’t want any flammable materials next to your home. Consider other materials such as pavers, concrete, or gravel.
- If you want to use plants or grass in this area, choose fire-resistant plants (see Tip #2) and keep everything well-watered.
- Keep it clean! Maintenance is KEY throughout your HIZ. Regularly clean out leaves, dried needles, and other vegetation (bark, cones, etc.) from the immediate zone. These items are the perfect fuel for embers, so you want to keep them away from the house.
- Remove stacks of firewood from up against the house or from porches and decks. Move firewood to the extended zone.
- Trim back any limbs within 10 feet of your chimney.
- Other sources of fuel: If you have a propane grill or gas cans around the home, move the propane tank and gas cans to the extended zone. Experts recommend using a shed in the extended zone to store these items with at least 10 feet of an ember-resistant zone around it.
- Pay attention to your deck. If you have combustible furniture, move it inside or swap it out with a non-combustible option (some type of metal). If you have cloth cushions on your furniture, bring these inside or remove them. Cushions provide a perfect environment for embers.
- Move it! Move garbage cans and all vehicles outside this 5-foot perimeter.
- If you have a fence or gate attached to your home, replace at least the 5 feet closest to your home with a non-combustible fence or gate material.
- Other tips to consider: Doormats and wooden-handled tools (brooms, rakes, etc.) in this zone can be fuel for embers. Put away your tools and choose a non-combustible doormat.
Intermediate Zone (5-30 feet from the home)
The California Department of Forestry and Fire Protection calls this the “lean, clean, and green zone.” The goal in this zone is to remove all dead plant materials and prevent fires from “laddering up” from low-lying vegetation to trees.
- You want to avoid dense vegetation in this area. Keep tree branches at least 10 feet from other trees. Maintain space between trees and shrubs and flammable objects (decks, furniture, swing sets). Dense vegetation can allow fire to travel up (“laddering”) from a lower plant (shrub) to a lower limb on a tree and cause a canopy fire or fling embers onto your home.
- Remove all dead material: leaves, needles, branches, etc. Trim back branches that are overhanging the roof. Clean out debris from underneath decks.
- All plants in this zone must be irrigated regularly, including the grass. Keep grass at 3 inches or lower.
Extended Zone (30-100 feet from the home. May go up to 200 feet)
The goal in this zone is to reduce the amount of fuel a fire can feed upon.
Here’s how to prepare the extended zone around your home:
- Annual grass should be kept to 4 inches or lower.
- Create proper spacing between trees and shrubs. (See Tip #3.)
- Remove as much debris as possible (leaves, twigs, cones, etc.). This debris is permitted in this zone, but keep it under 3 inches deep.
- Make sure any exposed stacks of wood have at least 10 feet of bare dirt that extends in every direction around the pile.
- Have a visible, reflective street address that firefighters can easily see.
- Make sure your driveway has at least 15 feet of vertical clearance and is at least 12 feet wide in case a fire truck needs to enter your property.
- Ask your fire department if they will evaluate your HIZ. Many fire departments in fire-prone areas offer this service.
2. Use fire-resistant plants
A fire-resistant landscape does not have to be devoid of color, texture, and beautiful vegetation. Fire-resistant plants are NOT fireproof. They can be killed by a fire, but they don’t serve as a significant fuel source for the fire as long as they are well-watered and well-maintained.
Oregon State University notes a few common characteristics of fire-resistant and flammable plants:
Fire-resistant landscape plants generally have these things in common:
- Have supple leaves and retain water well
- Don’t produce lots of dead matter or dead wood
- Have little sap, and the sap they have is low-odor and water-like
Flammable plants often share these characteristics:
- Bark that is papery or comes off easily
- Resinous sap with a strong odor
- Twigs, leaves, and needles that die and create lots of dead matter
As we’ve mentioned in the last section, maintenance is KEY. Give your plants the amount of water they need, and make sure they are healthy and pruned, if applicable.
According to the OSU Extension Service, these are a few of the fire-resistant plants that work well in Oregon:
Ground cover (under 18 inches): Yellow ice plant (Delosperma nubigenum), Hens and chicks (Sempervivum species), Creeping phlox (Phlox subulata)
Perennials: Sea thrift (Armeria maritima), Delphinium (Delphinium varieties), Hosta lily (Hosta species)
Shrubs (broadleaf evergreen): Orchid rockrose (Cistus purpureus), Oregon boxwood (Paxistima myrtifolia), Carol Mackie daphne (Daphne x burkwoodii var. “Carol Mackie”)
Deciduous shrubs: Dwarf burning bush (Euonymus alatus ‘Compactus’), Mockorange (Philadelphus species), Russian sage (Perovskia atriplicifolia)
Conifers: Western larch (Larix occidentalis), Ponderosa pine (Pinus ponderosa)
Note: Conifers are not usually included in fire-resistant landscaping lists. These two conifers have thick bark, and the foliage has a high moisture content. Be sure to prune lower branches up to 15-20 feet or slightly above the lower roofline if you plant these close to the house.
Deciduous trees: Amur maple (Acer ginnala), Hawthorn (Crataegus species), Canada red chokecherry (Prunus virginiana ‘Schubert’)
For more help with fire-resistant or native plants in the Pacific Northwest, check out these plant lists:
3. Maintain plant spacing
Think about horizontal and vertical spacing among the trees and shrubs throughout your landscape. This helps provide fuel breaks and prevents ladder fuels.
Horizontal spacing: The horizontal distance between trees and shrubs
Less than 20% slope:
- Trees: Keep 10 feet between trees.
- Shrubs: Keep two times your shrub’s height between shrubs. (Ex. If your shrubs are 5 feet tall, keep 10 feet of space between them.)
- Trees: Keep 20 feet between trees.
- Shrubs: Keep four times your shrub’s height between shrubs. (Ex. If your shrubs are 5 feet tall, keep 20 feet of space between them.)
Greater than 40% slope:
- Trees: Keep 30 feet between trees.
- Shrubs: Keep six times your shrub’s height between shrubs. (Ex. If your shrubs are 5 feet tall, keep 30 feet of space between them.)
Vertical spacing: The vertical distance between the trees and shrubs.
- Trees: Remove all limbs from the ground level up to at least 6 feet from the ground.
- Trees and shrubs: If you have shrubs underneath your trees, take three times the shrub height and trim all tree branches within that space. (Ex. If a 5-foot shrub is sitting underneath a tree, remove all tree branches up to 15 feet.)
4. Keep fencing and decks fire-safe
In an ideal world, all fencing and decks would be non-combustible. If you already have a deck or fence made with combustible materials, there are things you can do to reduce the risk of ignition.
Fencing is a prime surface for embers to land on and ignite. If you can retrofit the entire fence and use a non-combustible material, that is ideal. If not, here are a few tips:
- As we mentioned earlier, replace any fencing or gates that are attached to the house out to at least 5 feet.
- Remember, maintenance is KEY. Regularly clean below and around the bottom of the fence, removing all leaves and debris.
- Keep at least 1 inch of clearance between the soil and the bottom of the fence. This prevents decay and makes it easy to clean debris.
- Remove climbing plants and vines.
- Watch out for privacy fences. Embers like to lodge between the horizontal support and vertical boards, which may then ignite the fence.
If you’re interested in a non-combustible deck, some homeowners are choosing steel. A steel substructure with fiber cement decking is a popular choice in fire-prone areas.
If you want to stick with your existing deck, here are a few ways to reduce your chances of ignition:
- Remember, maintenance is KEY. Keep the deck surface and the area underneath the deck clean at all times.
- If your deck is on a slope, maintain proper plant spacing on the slope that faces the deck.
- Put in metal flashing to protect your home’s siding. Make sure it extends below and above the ledger board.
- Remove the one piece of deck board closest to the house and replace it with a non-combustible material.
5. Use hardscaping
Hardscaping is a way to create fire breaks and increase the functional living space in your lawn. Hardscaping is simply any non-living structure on your lawn, such as driveways, patios, pergolas, fencing, etc.
Hardscaping is especially beneficial in the immediate and intermediate zones (0-30 feet from the home). Here are a few examples of using hardscaping to create functional and defensible space:
- Build a paver patio and have a space to sit and eat with friends.
- Install a concrete walkway around part of the perimeter of the house to create a firebreak and a usable walking path.
- Use gravel in the flower beds in the immediate zone.
- Install a steel gazebo or pergola to provide a shaded social space. (Be sure to remove any fabric shades in the event of a fire.)
Why does my Portland home need fire-resistant landscaping?
Creating a defensible space around your home can save your home and help save homes around you, as well. It also provides an area for firefighters to work in to defend your home from an encroaching fire. Follow these tips to protect your home from ignition:
- Prepare your property to resist ignition
- Plant fire-resistant plants to keep your landscape beautiful and to reduce fuels
- Maintain proper spacing between plants around your home
- Make your fencing and decks more ignition-resistant
- Use hardscaping to increase your functional space and create firebreaks
If you’d rather spend your free time enjoying the parks, rivers, and mountains that Portlanders love, let one of our Portland lawn care professionals do the landscaping work for you. They can help you implement your HIZ plan to create a functional, ignition-resistant landscape so your home is ready when a fire strikes.