Kansas City may not be the first place you think of when you think of wildfire risk, but the drought of 2012 showed that Missouri is not exempt.
If you’ve spent time making sure your home, roof, and siding are ready to resist the flames, now it’s time to pay attention to your landscaping.
Consider these steps to make your home and landscape more resistant to damage during wildfire season.
- Design a defensible space
- Space plants properly
- Plant fire-resistant plants
- Choose fire-resistant mulch
- Make your decks and fencing fire-resistant
- Use hardscaping
1. Design a defensible space
It’s important to design a defensible space around your home. Defensible space provides a buffer around your home that slows the fire and makes it safer for firefighters if a fire invades your property.
The California Department of Forestry and Fire Protection (aka Cal Fire) divides home landscapes into three zones:
Zone 0 – Ember-Resistant Zone (0-5 feet from homes, decks, or outdoor structures)
Zone 0 is the most important zone to consider around your home. As the name suggests, you want to ensure that embers aren’t able to catch fire within five feet of your home or outbuildings.
Follow these landscaping tips to create an ember-resistant zone immediately around your home:
- Use non-flammable materials in this zone: well-watered turfgrass, brick chips, small stones or gravel, large rocks, hard walkways, and non-combustible decks or patios.
- Maintain this space often by removing dead leaves, needles, dead grass, and debris.
- Trim trees so they are not overhanging the house.
- Make sure deck furniture and planters are made of non-combustible materials. As an alternative option, bring combustible furniture inside.
- If a portion of your fence is attached to the house, replace a combustible material with a section of non-combustible fencing.
- Move firewood to Zone 2.
- Move vehicles and garbage cans to Zone 1 or 2.
- Make sure the area underneath the deck is clear of all flammable material and debris.
Zone 1 – Lean, Clean, and Green Zone (5-30 feet from outdoor structures)
Lean: Separate planted areas from each other. No dense vegetation.
Clean: Remove dead sticks, limbs, dead grass, leaves, and debris often.
Green: If you use vegetation in this zone, keep it green and well-watered.
Other tips for Zone 1:
- Keep turfgrass at 3 inches or lower.
- Maintain proper spacing between trees and shrubs. (Read on to learn more.)
- Use stone walls, driveways, ornamental beds, and gardens as firebreaks.
Zone 2 – The Reduced Fuel Zone (30-100 feet from outdoor structures)
The goal in managing this zone is to reduce the movement of fires in the tops of shrubs and trees.
Tips for Zone 2:
- Prune shrubs and trees properly to reduce “ladder” fires. (A ladder fire occurs when fire on a shrub or low-lying plant hits lower branches of a tree and spreads upward.)
- Outbuildings should be in this zone, at least 30 feet from the home.
- All outbuildings, stacks of firewood, and propane tanks should maintain at least 10 feet of ember-resistant space around them.
Whether you work with a landscape designer, arborist, or local Kansas City landscaping professional, reducing your fire risk is a team effort. As you consider how to reduce your risk, don’t forget your local fire department. Many fire departments in wildfire-prone areas will do free inspections to help to mitigate fire risks on your property.
Pro Tip: These are general guidelines. Some cities may have ordinances that are more or less stringent. Check with your local fire department to be sure.
2. Space plants properly
As you think about your vegetation, keep vertical and horizontal spacing in mind.
Vertical spacing: The vertical space between one plant and another
- Allow a minimum of six feet between the ground and the lowest tree branch.
If you have a shrub underneath a tree, the vertical space increases. In this case, multiply the shrub height times three. That is the minimum vertical space between the shrub and the tree’s lowest branch.
Example: A tree with a 5-foot shrub underneath.
5 x 3 = 15
There should be a minimum of 15 feet between the shrub and the bottom tree branches.
Question: Why is this important?
Answer: Fires that start on low-lying plants can easily climb up to higher plants (via a “ladder effect”) if the vegetation is too close together.
Horizontal spacing: The horizontal space between one plant and another
On land with a 20% slope or less:
- Trees: Keep a minimum of 10 feet of horizontal space between trees.
- Shrubs: Measure a shrub’s height. Multiply by two. Keep that distance between each shrub. Ex. Shrub height = 5. 5 x 2 = 10. Keep 10 feet between each shrub.
On land with a 20%-40% slope:
- Trees: Keep a minimum of 20 feet of horizontal space between trees.
- Shrubs: Measure a shrub’s height. Multiply by four. Keep that distance between each shrub. Ex. Shrub height = 5. 5 x 4 = 20. Keep 20 feet between each shrub.
Land with > 40% slope:
- Trees: Keep a minimum of 30 feet of horizontal space between trees.
- Shrubs: Measure a shrub’s height. Multiply by six. Keep that distance between each shrub. Ex. Shrub height = 5. 5 x 6 = 30. Keep 30 feet between each shrub.
3. Plant fire-resistant plants
Now that you know how to lay out a defensible space around your home, you may wonder, “What should I plant?” We’re glad you asked.
In general, fire-resistant plants have these things in common:
- Hold water in the leaves, or have leaves that are supple and moist
- Accumulate little or no dead matter or wood
- Have a low resin or sap content
Flammable plants have these characteristics:
- Have resinous, gummy sap
- Accumulate lots of dead material (twigs, needles, and leaves)
- Plant leaves have a strong smell when crushed
Here are a few Missouri plants that are good additions to your fire-resistant landscape:
- Eastern redbud (Cercis canadensis)
This smaller tree grows to a height of 20 to 30 feet tall and displays showy pink flowers in the spring. Like the flowering dogwood, it provides attractive fall color as well: its leaves turn from green to a light yellow in the fall.
- Flowering dogwood (Cornus florida)
Flowering dogwood is a familiar species to most Missourians. Its white flowers emerge in spring before its deep green foliage appears. This popular tree provides stunning fall color as its green leaves become various shades of red.
- River birch (Betula nigra)
This birch tree can tolerate full sun or partial shade and grows from 40-70 feet tall. An excellent shade tree, homeowners also enjoy that its toothed green leaves turn a rich yellow in the fall. Its bark is showy and peels off in creamy white sheets.
- Buffalo currant (Ribes aureum)
This deciduous shrub tolerates a variety of soil types and forms small, edible fruits that can be harvested in late summer.
- Adam’s needle (Yucca filamentosa)
Also known as needle palm, this shrub puts out tall, 5-8 foot white-flowered stalks in late spring.
- Trumpet Honeysuckle (Lonicera sempervirens)
Vining honeysuckle plant with orange-red to scarlet red flowers. A late spring bloomer.
- Three-leaved stonecrop (Sedum ternatum)
Sedum ternatum is a drought-tolerant ground cover that produces tiny, star-like flowers. It grows well in full sun to partial shade.
- Scarlet strawberry (Fragaria virginiana)
This ground cover puts out small white flowers in spring and may put on small red fruits, depending on the weather conditions that year. Prefers cooler spring and fall seasons.
Remember, no plant is fireproof, but be sure to choose ones that won’t fuel a fire.
4. Choose fire-resistant mulch
Mulches are a key element in most landscape designs, but if you live in a fire-prone area, you may wonder if this popular material is fire-safe.
An experiment done by the University of California Cooperative Extension and University of Nevada Cooperative Extension in 2008 showed that out of eight organic (plant-based) mulches tested, composted wood chips from a local company performed the best.
These composted wood chips demonstrated no active flames, but showed incidental flames and smoldering. The other organic mulches all demonstrated “active flaming combustion.” The one drawback is that it is not known if other brands of composted wood chips perform the same. Also, remember that composted wood chips are still combustible and may ignite other combustible materials (siding, plants, debris, etc.).
Remember, in Zone 0, the only approved options are non-combustible materials like concrete, brick, pavers, and a well-maintained lawn. Fire-resistant mulches, like these composted wood chips, should only be used in Zones 1 or 2.
5. Make your decks and fencing fire-resistant
Most people aren’t able to completely replace their combustible deck or fencing with a non-combustible structure. If this is you, there’s good news. In this section, we’ll discuss ways to retrofit an existing deck or fence and make the best choice if you’re building a new one.
Decks are usually attached directly to your home and are therefore within Zone 0, the ember-resistant zone. So, if you have a wooden deck, this zone is no longer ember-resistant.
There are a few options. If you live in a very high-risk area, you may want to consider a new deck. Building a steel substructure with fiber cement decking is a non-combustible option.
If your risk is lower, there are a few ways to reduce the chances that your combustible deck will ignite.
- Pay attention to what is on top of and underneath the deck.
Combustible materials such as wooden planters, wood seating, or debris are fire hazards. Consider replacing furniture and planters with non-combustible options (metal, for example). Routinely keep the top of the deck and ground underneath free from leaves and debris.
- Create a Zone 0 around and underneath the deck.
Consider using gravel, crushed stone, or brick chips, etc., underneath and around the deck. Or, lay a walkway around the deck and plant turfgrass beside it to create a 5-foot perimeter.
- Maintain slopes properly
If your deck sits on a slope, keep in mind the recommendations about spacing in point #2. If the slope has trees, bushes, or other vegetation, keep this vegetation well maintained and properly spaced (see #2) to keep flames from reaching the deck.
- If your deck is wooden, a plastic composite, or otherwise flammable, install metal flashing.
This flashing should cover at least 6 inches of the siding above and below. Also, use a non-combustible material for the deck board closest to the house.
- Leave ¼ inch between redwood or cedar deck boards.
This makes it easier to sweep debris through the deck boards. (Be sure to clean the area under the deck regularly as well.)
Here are a few tips to reduce the risk that your fence will ignite:
- Keep weeds, leaves, and other debris cleaned up from the base of the fencing.
- If you have a fence that attaches to the outside of your home, the last 5 feet (minimum) closest to your house should be made from a noncombustible material.
- Keep the fence free from vines and other climbing plants.
- Privacy fences are particularly dangerous. Embers easily lodge at the joint of the horizontal and vertical boards and ignite the fence.
- Keep at least 1 inch between the soil and wooden fence boards to prevent decay and make it easy to clean debris.
6. Use hardscaping
Hardscaping simply refers to any non-living, hard element in your lawn (driveway, pergola, patio, walkway, etc.) Many homeowners build hardscaping to enhance their outdoor space and add non-combustible elements to Zones 0 or 1.
Not only can these elements be constructed from non-combustible materials, they often serve as outdoor living space in your lawn. If you spend much of the year enjoying the outdoors, hardscaping adds usable, outdoor living space for your family and friends to enjoy.
Hardscaping can be especially helpful in Zone 0, the ember-resistant zone. Homeowners often add walkways or sidewalks around part of the perimeter to increase usability and provide a necessary firebreak. Outdoor decks are another popular Zone 0 addition. (See #3 for more details on decking precautions.)
Want to find out more?
Here are a few resources that can help you prepare for a wildfire:
- Ready.gov – Resources for wildfire preparedness
- Readyforwildfire.org – In this article, we’ve only discussed how to prepare your landscaping, but this resource also talks about how to prepare your home.
Why does my Kansas City home need fire-resistant landscaping?
There is little you can do to stop a wildfire from coming toward your home, but you can do something to prevent your home and landscape from catching fire. As Smokey Bear might say, “YOU have the responsibility to protect your home from wildfires.”
Protecting one of your biggest investments is all about planning and design – from selecting the right plants and properly spacing them to selecting the right design and features around your home. It’s worth it.
If you’d rather spend time perfecting your backyard rib recipe or watching your favorite Kansas City sports team, let one of our Kansas City landscaping experts help make your landscape more beautiful, functional, and firewise.
Main Photo Credit: Richard Lewis | Flickr | CC BY 2.0