Los Angeles firestorm a reminder of how wildfire can spread with aid of landscape
Several rows of Italian cypress and a palm tree, among others, tower over a home in northeast Sacramento County. Kathy Morrison
Under the right circumstances, any plant can burn. For our region, which still has vivid memories of the Paradise, Napa and Santa Rosa conflagrations, the Los Angeles fires offer a sad reminder that hurricane-force winds driving a wildfire can cut down anything in its path.
But: Watch a news video of a palm tree burning on top and spraying embers like a blaze sprinkler -- in a street not yet on fire otherwise -- and you'll realize that some plants (especially trees) can be complicit in the spread of fire.
The organization Fire Safe Marin has an excellent website on preparing for and adapting life to wildfires. One informative page talks about How Homes Ignite -- and it's often from embers, as opposed to radiant heat or direct flames. Keeping the airborne embers from igniting the roof or plants and blocking them from entering the attic or ventilation system appears to be crucial.
Elsewhere on the site is a section on how to Create a Fire Smart Yard. This gets into the discussion of "defensible space," certainly a familiar term to Placer and El Dorado residents. It basically involves creating a buffer between a building (such as a house) and any combustible material. "Proper defensible space provides firefighters a safe area to work in to defend your home," the page notes.
Plant selection and location is important for defensible space. But, the writers point out, "A plant’s environment and maintenance generally have more influence on the combustibility of the plant than does its characterization as fire safe or not fire safe."
Notably, the Los Angeles region since July has had almost no measurable rain. So landscaping likely already was dry and stressed before the fierce winds started up.
All other things being equal, some trees common in California are more prone to burn than others. Along with palms, the common fire-prone non-natives include eucalyptus, cedars, cypress, firs, junipers and spruces. Natives can burn easily, too, if not properly maintained; these include manzanitas, Douglas-firs (which are not true firs) and California bays.
So looking around my own suburan neighborhood, where most of the ranch houses are 50 to 60 years old, I see good, OK and terrible choices in landscape trees, in terms of fire resistance. Citrus trees, Chinese pistache, pineapple guava and western redbud are among the ones here that are considered fire smart.
California's native oaks, which evolved with fire, are well-represented. Mature valley and blue oaks are considered fire resistant, though a bit less so than coast live oaks. Coast redwoods contain tannin -- a natural flame retardant -- in their bark and heartwood; they really shouldn't be planted here in the Central Valley, but the several trees around the neighborhood all look healthy and well-irrigated.
On the flip side, there are more than a few rows of Italian cypress trees and bushy cedars that would worry me if they were next door. (Side note: Firefighters reportedly refer to Italian cypress as "Roman candles.") Mature oleanders abound. Pine tree branches rest on roofs. And what is with all the palm trees? Just from my front walkway, I can spot seven of them, of various heights. Yikes.
For more information on fire-smart planting, I found these resources:
-- Farmer Fred Hoffman's "Firescaping" episode (No. 115, from June 29, 2021) on his "Garden Basics with Farmer Fred" podcast. (There is a transcript.) He has a great conversation with Douglas Kent, author of "Firescaping: Protecting your Home with a Fire Resistant Landscape." Among their topics, they note the high flammability of gorilla hair mulch and the surprising fact that homes can burn from the inside out if embers get through vents, gaps in the garage or melted vinyl windows. Eliminating fuel (dead branches inside hedges, for example) and "fuel ladders" next to homes is crucial, Kent notes.
-- The UCANR Fire Network website, especially the Wildfire Preparedness section. It has a page devoted to choosing "fire resilient" plants, a term I like. There are several helpful links at the bottom of the page, including:
-- "Home Landscaping for Fire," UCANR Publication No. 8228, an easily printable pdf that includes an excellent list of annual maintenance reminders. It summarizes: "Lack of attention to these recommendations can result in plants accumulating dead twigs, leaves and branches, whether or not they are characterized as 'fire-resistant.' Lack of maintenance can easily result in vegetation that is very flammable."
-- Finally, Wikilawn's "8 Fire-Resistant Landscaping Ideas for Sacramento" is a good summary of basics I read elsewhere.
Northern California understands like nowhere else what's happening in the L.A. area this week. We've been there -- and likely will be again. Stay safe, everyone.
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Food in My Back Yard Series
May 6: Maintain soil moisture with mulch for garden success
April 29: What's (already) wrong with my tomato plants?
April 22: Should you stock up on fertilizer? (Yes!)
April 15: Grow culinary herbs in containers
April 8: When to plant summer vegetables
April 1: Don't be fooled by these garden myths
March 25: Fertilizer tips: How to 'feed' your vegetables for healthy growth
March 18: Time to give vegetable seedlings some more space
March 11: Ways to win the fight against weeds
March 4: Potatoes from the garden
Feb. 25: Plant a fruit tree now -- for later
Feb. 18: How to squeeze more food into less space
Feb. 11: When to plant? Consider staggering your transplants
Feb. 4: Starting in seed starting
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Garden Checklist for week of May 4
Enjoy this spring weather – and get gardening!
* Plant, plant, plant! It’s prime planting season in the Sacramento area. Time to set out those tomato transplants along with peppers and eggplants. Pinch off any flowers on new transplants to make them concentrate on establishing roots instead of setting premature fruit.
* Direct-seed melons, cucumbers, summer squash, corn, radishes, pumpkins and annual herbs such as basil.
* Harvest cabbage, lettuce, peas and green onions.
* In the flower garden, direct-seed sunflowers, cosmos, salvia, zinnias, marigolds, celosia and asters. (You also can transplant seedlings for many of the same flowers.)
* Plant dahlia tubers. Other perennials to set out include verbena, coreopsis, coneflower and astilbe.
* Transplant petunias, marigolds and perennial flowers such as astilbe, columbine, coneflowers, coreopsis, dahlias, rudbeckia and verbena.
* Keep an eye out for slugs, snails, earwigs and aphids that want to dine on tender new growth.
* Feed summer bloomers with a balanced fertilizer.
* For continued bloom, cut off spent flowers on roses as well as other flowering plants.
* Add mulch to the garden to maintain moisture. Mulch also cuts down on weeds. But don’t let it mound around the stems or trunks of trees or shrubs. Leave about a 6-inch to 1-foot circle to avoid crown rot or other problems.