Fire-wise landscaping should focus on creating a ‘defensible space’ around your home. In “Firewise Plant Materials,” a fact-sheet for the CO Cooperative Extension, F. C. Dennis defines this: “Defensible space is the area between a structure and an oncoming wildfire where nearby vegetation has been modified to reduce a wildfire’s intensity,” and therefore, reduces risk to property.
These modifications could be accomplished by: increasing moisture content, choosing the most fire-resistant plants, spacing plants in smaller, disconnected groups, and proper maintenance and clean-up.
Some specific suggestions:
“A plant’s moisture content is the single most important factor.” The fire-resistance of a plant is dependent on the moisture content in its cells, so it is most beneficial to water deeply in hot, dry weather, especially in late summer, which tends to be fire season.
The flammability of plants varies a great deal. Resinous plants like conifers (Juniper, Spruce, Pine, Fir, Douglas Fir, etc.) get a low rating for fire-resistance because their resinous sap is very flammable. Juniper shrubs or trees should not be planted close to a house.
Large trees are also given a low rating because if they catch fire, they can ignite other plants, fences and buildings. However, the leaves of deciduous trees contain more moisture and are less flammable than conifers. Therefore, site big trees where they will cast shade from some distance from structures.
Harlequin’s Gardens staff has, from many sources, compiled and edited a very extensive list of plants with their fire-resistant ratings. The list is nearly complete, and we update it frequently; see the current list HERE.