Defensible Space Landscaping in the Urban/Wildland Interface:
A compilation of fire performance ratings of residential landscape plants

Introduction

This vegetation guide was developed as part of a larger fire mitigation research project under way at the University of California Forest Products Laboratory. The purpose of this guide is to provide information on the properties of some common California landscaping plants that can be used to determine how a particular plant will behave when burned. It is a referenced database that compiles the information found in available lists and supplements information on plant characteristics that are known to affect fire performance.

This document is presented as a framework for plant selection, not as the definitive word for plant selection. Guidelines and recommendations for vegetation selection in high fire hazard areas are available but close examination of these existing lists reveals little scientific basis and often conflicting information. It appears that many of the lists are primarily based on anecdotal information. A literature search identified more than 25 lists of plants recommended for use in high fire hazard environments. Some of these lists have been generated by categorizing plants by various growth characteristics, but in many cases it is not clear what characteristics were considered in the selection criteria. Without any verification of their reliability, these lists are often distributed by fire departments and state and local agency offices. The total number of species included in all lists referenced is 598. Of those, 147 species have a favorable fire performance rating in three or more references, 17 species had an unfavorable fire performance rating in three or more references, and 53 species had conflicting fire performance ratings within the references. This document summarizes existing recommendations and where possible identifies the plant characteristics on which the recommendation is based.

How to Use this Document

Information on the expected fire performance of specific plants can be obtained by looking up the plants, by scientific name, in the fire performance lists and then referring to the database to obtain more detail on the mature plant characteristics.

The database information includes available information on mature plant characteristics, drought resistance, and erosion control. The drought resistance information is included because the vigor of the plant is lower and the amount of dead material higher in plants that are stressed by drought, creating a lower than expected fire performance. If drought information was not specifically cited in the references it can be inferred from the recommended climate zones which are based on those published in the Sunset Western Garden Book (Brenzel 1995). Erosion control information is included because many high-fire risk zones include steep slopes and both fire performance and erosion control need to be considered in the selection of plants.

Intended Use

This document is offered as a reference guide to landscaping in defensible space. It is not intended to provide the final word on landscaping decisions but rather to provide as much information as possible on the factors known to effect the fire performance of plants. Because this guide is a compilation of information from a variety of sources, there are often conflicting recommendations. These are identified as conflicts and also the source of the information is referenced. The goal is to provide a major reference tool that can aid in defensible space landscape vegetation selection decisions. If a user has reason to believe that a recommendation in this guide is not appropriate or does not agree with the user’s experience, then the plant should be re-evaluated for the individual situation to reflect the user’s assessment.

It is important to consider the overall plant characteristics when landscaping in fire-prone areas, particularly for plants with fire ratings that are inconsistently reported. The list of plants noted as having discrepancies in fire ratings should be evaluated individually, basing judgment of suitability on the mature plant characteristics that are known to influence a plant’s ability to resist burning, such as, moisture content, surface area/volume, chemical content, arrangement, and accumulation of dead matter and, equally as significant, how the plant will be maintained. It is also important to consider the proximity to the structure and the climate zone(s) in which the plant thrives, and also the fact that mature plant characteristics can easily be influenced by the climate, available irrigation, and maintenance practices.

Future Work

This vegetation reference guide has been constructed for use by individuals, home owners, municipalities, and landscape professionals. The document is the result of preliminary work by the University of California Forest Products Laboratory. As more information becomes available, the guide will be updated. It is clear that the existing information on which the fire risk and performance ratings of plants are based is incomplete and often anecdotal. There is a great need for scientifically-based testing of landscape plants to improve the database of recommended species. Work is under way to create a vegetation test protocol and perform vegetation testing to accumulate such scientific data on the fire performance of commonly used landscape plants.

References

Contents:

Plants with a Favorable Fire Performance Rating

The following list of plants contains those found in the references that were recommended for use in fire prone environments by at least 3 references. All of the plants listed here were given either a high or moderate fire resistance rating in the references where a rating was assigned, or found listed in the references that categorized plants as fire resistant without assigning a degree of resistance. In most cases, the terms used in the ranking were not defined, and if they were, there is no agreed upon standard definition. For this reason, the plants are listed in this chapter without any attempt to rank them.

The list is sorted by plant form -- groundcovers, shrubs, trees, etc. Some species may appear twice (e.g. once as a groundcover and then again as a shrub) because they have properties attributed to both forms. For a complete description of the plant, including its mature characteristics, climate zones, and information on erosion control and drought tolerance, please refer to the landscape vegetation database.

It is important to note that a plant’s fire performance can be seriously compromised if not maintained. Plants that are not properly irrigated or pruned, or that are planted in climate areas not generally recommended for the plant, will have increased fire risk and will likely make the mature plant undesirable for landscaping in high fire hazard zones.

 

Table 1. Plants with a favorable fire performance rating in 3 or more references.

Scientific Name

Common Name

Plant Type

Plant Form

Reference #

Achillea millefolium white

White yarrow

perennial

shrub

25, 40,41, 53

Achillea tomentosa var. Moonshine

Woolly yarrow

perennial

groundcover

7,11,12,13,23,25,26,28,32,35,36,37,39

Aeonium decorum

Aeonium

succulent

shrub

7,10,38,53

Aeonium simsii

Aeonium

succulent

shrub

7,10,53

Aesculus californica

California buckeye

deciduous

tree

11,15,17

Agapanthus 'Peter Pan'

Lily of the Nile, dwarf

evergreen

shrub

9,10,25

Agave americana 'Alba Picata'

Century plant

succulent

shrub

9,25,37

Agave victoriae-reginae

Agave

succulent

shrub

7,10,53

Ajuga reptans

Carpet bugle

perennial

groundcover

7,9,10,11,17,23,28,35,36,40,41,53

Alnus rhombifolia

White alder

deciduous

tree

9,11,17,25,53

Aloe arborescens

Torch aloe

succulent

shrub

9,25,53

Aloe aristata

Aloe, Dwarf aloe

succulent

shrub

7,10,40,41,53

Aloe brevifolia

Aloe

succulent

shrub

7,10,40,41,53

Arbutus menziesii

Madrone

evergreen

tree

11,15,17

Arbutus unedo

Strawberry tree

evergreen

tree

8,9,11,12,17,25,30,40,41,42,53

Arctotheca calendula

Silver spreader

evergreen

groundcover

7,8,9,10,11,12,18,20,21,23,24,25,26,28,30,31,34,35,36,37,38,40,41,42,53

Armeria maritima

Thrift, Common thrift

evergreen

groundcover

9,10,11,12,15,25,40,41

Artemisia caucasica

Silver spreader

evergreen

shrub

9,10,12,23,28,30,35,36,37,38,42,53

Artemisia pycnocephala

Sandhill sage

evergreen

shrub

6,11,16,25

Asarum caudatum

Wild ginger

perennial

shrub

11,15,40,41

Atriplex canescens

Four-wing saltbush

evergreen

shrub

5,6,16

Atriplex lentiformis breweri

Saltbush

deciduous

shrub

5,11,19

Atriplex semibaccata

Saltbush

evergreen

shrub

7,10,11,13,21,23,24,27,28,35,36,37,40,41,42

Callistemon viminalis

Weeping bottlebrush

evergreen

tree

26,30,37

Campsis radicans

Trumpet vine, Trumpet creeper

deciduous

vine

12,26,30,32,37

Carpobrotus edulis

Ice plant, Hottentot fig, Sea fig

succulent

groundcover

7,9,10,11,23,24,28,31,35,36,37,53

Ceanothus thyrsiflorus

Blueblossom

evergreen

shrub

11,14,15

Centranthus ruber

Red valerian, Jupiter's beard

evergreen

shrub

8,11,25,40,41

Cerastium tomentosum

Snow in summer

evergreen

groundcover

7,10,17,24,30,37,39,40,41,53

Ceratonia siliqua

Carob, St. John's beard

evergreen

tree

5,8,9,11,13,22,34,37,42

Cercis occidentalis

Western redbud

evergreen

tree

8,9,11,12,15,17,25,30,34,40,41,42,53

Cistus purpureus

Orchid rockrose, Purple rockrose

evergreen

shrub

25,30,53

Cistus villosus prostratus (C.salviifolius)

Purple rockrose, Prostrate rockrose

evergreen

groundcover

9,19,22,37

Citrus spp.

Citrus

evergreen

tree

8,12,30,34,40,41

Convolvulus cneorum

Bush morning glory

evergreen

shrub

8,9,11,12,30,32,39,40,41,42,53

Coprosma kirkii

Creeping coprosma

evergreen

groundcover

8,11,12,18,30,40,41,53

Cotoneaster congestus

Likiano

evergreen

shrub

40,41,53

Cotoneaster dammerii

Bearberry cotoneaster

evergreen

groundcover

9,25,40,41

Crassula argentea

Jade plant

succulent

groundcover

9,25,33

Crassula lactea

Crassula

succulent

groundcover

7,9,10,25,36,53

Crassula multiclava

Crassula

succulent

groundcover

7,9,10,25,36,38

Crassula tetragona

Crassula

succulent

groundcover

7,10,36,53

Delosperma alba

White trailing ice plant

succulent

groundcover

7,9,10,11,18,22,23,24,26,28,35,36,37,39,,40,41,42,53

Dietes bicolor

Wild yellow iris, African iris

evergreen

shrub

9,25,40,41

Dietes vegeta

Fortnight lily

evergreen

shrub

9,11,12,25,40,41

Diplacus longifolius (Mimulus sp.)

Monkey flower

perennial

shrub

11,15,17,25,40,41,42,53

Drosanthemum floribundum rosea

Ice plant, Rosea ice plant

perennial

groundcover

8,9,10,11,23,25,26,31,35,36,40,41,42,53

Drosanthemum hispidum

Rosea ice plant

perennial

groundcover

7,9,10,18,23,24,25,28,36,39,40,41,53

Drosanthemum speciosum

Drosanthemum, Dew flower

perennial

groundcover

7,38,53

Duchesnea indica

Mock strawberry

perennial

groundcover

8,9,11,12,25,40,41

Dymondia margaretae

Dymondia

evergreen

groundcover

8,9,25

Erigeron karvinskianus

Santa Barbara daisy, Fleabane

perennial

groundcover

9,12,17,25,40,41

Eriodictyon trichlocalyx

Yerba santa, Hairy yerba santa

 

shrub

5,13,19

Eriophyllum confertiflorum

Golden yarrow

perennial

shrub

40,41,53

Eschscholzia californica

California poppy

perennial

groundcover

8,9,11,12,25,42,53

Eunymous fortunei radicans

Winter creeper, Common winter creeper

evergreen

shrub

7,10,30,41

Feijoa sellowiana

Pineapple guava

evergreen

tree

89,11,12,17,25,30,40, 41,42,53

Festuca rubra

Creeping red fescue

perennial

groundcover

8,9,11,12,15,25,40,41

Fragaria chiloensis

Wild strawberry, Sand strawberry, ornamental

evergreen

groundcover

7,8,9,10,11,23,25,28,35,36,39,40,41,53

Fraxinus spp.

Ash

deciduous

tree

18,34,40,41

Fremontodendron spp.

Fremontia, Flannel bush

evergreen

shrub

11,15,17

Galvezia speciosa

Showy Island snapdragon, Hummingbird flower

evergreen

shrub

8,11,12,15,25,30,53

Gazania ringens leucolaena (G. uniflora)

Trailing ganzania

perennial

groundcover

7,10,11,12,23,24,25,27,28,35,36,37,38,39,40,41,42,53

Gazania uniflora (G.ringens leucolaena)

Trailing ganzania

perennial

groundcover

7,10,11,12,23,24,25,27,28,35,36,37,38,39,40,41,42,53

Grindelia stricta

Gum plant,Coastal wild gum

perennial

groundcover

40,41,53

Grindelia stricta venulosa

Coastal wild gum

perennial

shrub

25,40,41

Helichrysum petiolatum

Licorice plant, Curry plant

perennial

shrub

8,11,17,25,40,41

Hemerocallis spp.

Daylily

deciduous or evergreen

shrub

8,9,11,12,14,25,40,41

Hesperaloe parviflora

Red yucca

evergreen

shrub

9,25,40,41

Heuchera maxima

Island alum root, Coral bells

perennial

groundcover

8,12,15,25,40,41

Iberis sempervirens

Evergreen candytuft, Edging candytuft

evergreen

groundcover

40,41,53

Iris douglasiana

Pacific coast iris, Douglas iris

bulb

shrub

11,15,17,40,41

Isomeris arborea (Cleome isomeris)

Bladderpod, Bladderbush, Burrofat

evergreen

shrub

6,16,53

Kniphofia uvaria

Red hot poker

perennial

shrub

8,9,11,12,17,25,40,41

Lampranthus aurantiacus

Trailing ice plant, bush gold, bush ice plant

succulent

groundcover

7,9,10,22,25,39,53

Lampranthus filicaulis

Redondo creeper

succulent

groundcover

7,10,22,53

Lampranthus spectabilis

Trailing ice plant

succulent

groundcover

7 ,9,10,11,22,24,25,38,42,53

Lantana camara & cultivars

Trailing lantana, Yellow sage

evergreen or annual

groundcover

9,23,28,35,36,53

Ligustrum texanum

Texas privet

evergreen

shrub

11,30,40,41

Limonium perezii

Statice, Marsh rosemary, Sea lavender

perennial

shrub

8,9,11,12,14,25,30,40,41,53

Lippia canescens

Carpet grass, Lippia

perennial

groundcover

7,41,42

Liriope gigantea

Giant turf lily

perennial

groundcover

8,25,40,41

Lonicera japonica 'Halliana'

Hall's honeysuckle

evergreen

groundcover

7,10,53

Macadamia hybrids

Macadamia nut, Queensland nut

evergreen

tree

9,11,25,40,41

Mahonia repens

Creeping mahonia

evergreen

shrub

8,11,40,41

Malephora crocea

Ice plant, Croceum ice plant

succulent

groundcover

7,8,9,10,11,22,23,24,26,28,31,35,36,40,41,42,53

Malephora luteola

Yellow trailing ice plant

succulent

groundcover

7,10,22,24,40,41,53

Metrosideros excelsus

New Zealand Christmas tree,Pohutukawa

evergreen

tree

11,12,18,30,40,41,42,53

Mimulus longiflorus (Diplacus longiflorus)

Monkey flower

perennial

shrub

11,17,15,25,40,41,42,53

Myoporum parvifolium prostrata

Creeping boobyalla, Myoporum

evergreen

groundcover

8, 9,10,11,12,21,23,24,25,28,35,36,38,39,40,41,42,53

Myrica californica

Wax myrtle, Pacific wax myrtle, California wax myrtle

evergreen

shrub

11,15,17

Nerine masonorum

Nerine

bulb

shrub

8,9,11,25

Nerium oleander

Oleander

evergreen

shrub

5,12,13,17,11,26,27,30,32,33,42,40,41

Oenothera berlandieri

Mexican evening primrose

perennial

groundcover

8,11,25,40,41

Osteospermum fruticosum

Trailing South African daisy, Freeway daisy

perennial

groundcover

1,5,6,7,9,10,11,13,16,22,23,24,28,30,34,36,38,39,40,41,42

Pelargonium peltatum

Ivy geranium

perennial

groundcover

7,9,10,11,12,23,24,25,28,36,38,40,41,53

Phyla nodiflora

Lippia

perennial

groundcover

8,9,10,11,12,23,28,35,36,40,21,41

Pittosporum crassifolium

Dwarf karo

evergreen

shrub

25,40,41

Pittosporum tobira

Mock orange, Wheeler's mock orange

evergreen

shrub

11,12,25,40,41

Populus spp.

Aspen, Cottonwood, Poplar

deciduous

tree

11,15,18

Populus tremuloides

Quaking aspen

deciduous

tree

9,11,15

Portulacaria afra

Purslane tree, Elephant's food

succulent

groundcover

7,9,10,24,40,41,53

Potentilla tabernaemontanii (P.verna)

Spring cinquefoil

evergreen

groundcover

7,10,37,40,41,53

Prunus ilicifolia

Holly-leaved cherry

evergreen

shrub

8,11,12,15,26,30

Prunus lyonii

Catalina cherry

evergreen

shrub

5,8,9,11,12,13,25,37,40,41,53

Prunus spp.

Plum, Peach, Cherry, Apricot, Evergreen cherry

evergreen

tree

11,15,42

Punica granatum

Pomegranate

deciduous

shrub

11,30,40,41,42,53

Punica granatum 'Nana'

Dwarf pomegranate

deciduous

shrub

9,8,11,12,25

Pyracantha 'Santa Cruz'

Pyracantha, Firethorn

evergreen

shrub

8,11,12,25,40,41

Quercus agrifolia

Encina, Coast live oak, California live oak

evergreen

tree

8,9,11,15,17,25,30,31,33,53

Rhamnus alaternus

Italian buckthorn

evergreen

shrub

5,9,11,12,13,22,30,32,40,41,42,53

Rhamnus californica

Coffeeberry

evergreen

shrub

9,11,12,15,17,25,26,30,53

Rhamnus crocea

Spiny redberry, Redberry, Hollyleaf redberry, Red-berried buckthorn

evergreen

shrub

11,25,53

Rhododrendron occidentale

Western azalea

evergreen

shrub

17,40,41

Rhus integrifolia

Lemonade berry

evergreen

shrub

8,9,12,13,14,15,22,26,37,40,41,53

Rhus lancea

African sumac

evergreen

tree

8,11,12,26,37,40,41

Ribes viburnifolium

Evergreen currant, Catalina perfume

evergreen

shrub

8,9,11,15,17,25,30,53

Salvia sonomensis

Sonoma sage, Creeping sage

perennial

shrub

7,9,10,11,15,16,21,25,27,38,40,41,42,53

Santolina chamaecyparissus

Santolina, Lavender, Gray lavender

evergreen

shrub

7,9,10,17,23,24,25,32,36,37,40,41,42,53

Scaevola 'Muave Clusters'

Fan flower

perennial

groundcover

8,9,11,12,25

Schinus molle

Peruvian pepper tree, California pepper tree

evergreen

tree

5,9,11,13,17,22,25,30,37,40,41,53

Schinus terebinthifolius

Brazilian pepper tree

evergreen

tree

5,9,11,12,22,40,41,42,53

Sedum acre

Goldmoss sedum

succulent

creeper

7,10,53

Sedum album

Green stonecrop

succulent

creeper

7,10,53

Sedum brevifolium

Stonecrop

succulent

groundcover

7,9,24,25

Sedum confusum

Stonecrop, Sedum

succulent

groundcover

7,10,24,40,41,53

Sedum rubrotinctum (S. guatemalense)

Brown bean, Pork and beans

succulent

groundcover

7,10,24,38,40,41,53

Sedum spathulifolium

Stonecrop

succulent

groundcover

11,15,25

Senecio mandraliscae

Blue ice plant

succulent

shrub

9,10,25

Senecio serpens (Kleinia repens)

Senecio, Dusty miller, Blue-chalksticks

succulent

shrub

7,24,40,41,53

Simmondsia chinensis

Pignut, Jojoba, Goatnut

evergreen

shrub

9,11,15,40,41,42,53

Sisyrinchium bellum

Yellow-eyed grass, Blue-eyed grass

perennial

grass

11,15,40,41,53

Sisyrinchium californicum

Yellow-eyed grass

perennial

grass

15,25,41

Solanum jasminoides

Potato vine

evergreen or deciduous

vine

8,9,12,17,26,30,37,40,41

Solanum xanti

Purple nightshade

evergreen

shrub

17,40,41

Strelitzia reginae

Bird of paradise

perennial

shrub

27,40,41

Symphoricarpos mollis

Waxberry, Creeping snowberry, Trip vine

deciduous

groundcover

11,15,40,41

Tecomaria capensis

Cape honeysuckle

evergreen

vine

8,11,26,37,40,41,42,53

Thymus praecox articus

Mother of thyme, Creeping thyme

perennial

shrub

9,10,23,36,40,41

Thymus pseudolanuginosus (T.lanuginosus)

Woolly thyme, Thyme

perennial

groundcover

7,10,23,28,35,36

Trachelospermum jasminoides

Star jasmine

evergreen

groundcover

9,11,12,17,25,40,41,53

Trichostema lanatum

Woolly blue curls, Romero

perennial

shrub

8,11,12,15,25,26,42,53

Trifolium fragiferum

O'Connor's legume

perennial

groundcover

40,41,53

Tulbaghia violacea

Society garlic

perennial

shrub

8,9,25,40,41

Vinca major

Periwinkle

perennial

groundcover

7,9,10,11,20,23,24,30,34,36,38,39,53

Vinca minor

Dwarf periwinkle myrtle, Dwarf running myrtle

perennial

groundcover

7,10,11,23,24,28,30,36,38,39,53

Zauschneria californica

California fuschia, Hummingbird flower

perennial

shrub

9,11,17,40,41,53

 

 

Plants with an Unfavorable Fire Performance Rating

The following list of plants contains those found in the references that are definitely not recommended for use in fire prone environments by at least 3 references. All of the plants listed here were given either a low fire resistance rating in the references where a rating was assigned, or found listed in the references that categorized plants as being fire prone, without assigning any relative degree of resistance.

The list is sorted by plant form -- groundcovers, shrubs, trees, etc. Some species may appear twice (e.g. once as a groundcover and then again as a shrub). For a complete description of the plant, including its mature characteristics, climate zones, and information on erosion control, drought tolerance and cold tolerance, please refer to the landscape vegetation database.

Characteristics of plants not recommended for fire prone areas.

The plants in this group have some commonly shared characteristics. Most of these plants are characterized by:

  • a high surface area to volume ratio.
  • a low moisture content.
  • a high percentage of dead matter or debris.

Plants that possess all of these characteristics are likely to have an unfavorable fire performance rating. Comparison of the general characteristics of a plant not included in this list with those listed above could result in a decent estimate of the plant’s fire performance.

It is possible that a plant listed as fire resistant, but allowed to grow unchecked and poorly maintained could possess the characteristics listed above and therefore be a liability. Proper maintenance of landscaping is crucial and cannot be overlooked. Conversely, it is also possible that a plant with an unfavorable rating could perform well with special irrigation and maintenance regimes. However this approach is not advisable since long term irrigation and maintenance cannot be guaranteed.

 

Table 2. Plants with an unfavorable fire performance rating in 3 or more references.

Scientific Name

Common Name

Plant Type

Plant Form

Reference #

Abies spp.

Fir

evergreen

tree

4,8,40,41

Adenostoma fasciculatum

Greasewood chamise

evergreen

shrub

3,4,8,9,30,40,41,42

Adenostoma sparsifolium

Red shanks

evergreen

shrub

8,9,30,42

Coprosma pumila

Prostrate coprosma

evergreen

groundcover

9,25,53

Cortaderia selloana

Pampas grass

evergreen

grass

4,8,9,40

Eriogonum fasciculatum

California buckwheat

perennial

shrub

4,40,41,42

Eucalyptus globulus

Eucalyptus globulus, Blue gum

evergreen

tree

4,9,8

Larix spp.

Larch

deciduous

tree

8,40,41

Lonicera japonica

Japanese honeysuckle

evergreen

vine

8,40,41

Palms

Palm

evergreen

tree

8,40,41

Picea spp.

Spruce

evergreen

tree

4,8,40,41

Pickeringia montana

Chaparral pea

evergreen

shrub

8,40,41

Pseudotsuga menziesii

Douglas-fir

evergreen

tree

4,40,41

Spartium junceum

Spanish broom

evergreen

shrub

4,40,41

Taxus spp.

Yew

evergreen

tree

4,40,41

Thuja spp.

Arborvitae

evergreen

tree

4,8,40,41

Tsuga spp.

Hemlock

evergreen

tree

8,40,41

 

List of References for Plant Fire Performance Ratings:

Ref #

Author

Title

Year

Publisher

Reference Summary

1

California Department of Forestry

Fire Safe: Inside and Out

Date Unknown

California Department of Forestry Publication

Defines fire retardant plants as those easily maintained and pruned, drought tolerant in some cases, can be grown without accumulating dead branches, needles or leaves, have a low sap or resin content, and grow close to the ground.

2

Gaidula, Peter

Wildland Fuel Management Guidelines for the CA State Park System

1976

California Department of Parks and Recreation

This reference does not offer a definition of fire retardance with respect to plants, however it offers suggestions of certain plant characteristics to keep in mind when clearing brush to reduce fire hazard: plant vigor, poisonous plants, effects of plants on soils, value for wildlife food and cover, aesthetic values, and relative flammability.

3

Tarbes, J.A.

Physical Characteristics of Chamise in Relation to Flammability and Combustibility

1980

San Francisco State University, CA

Defines fire performance characteristics of chamise species only.

4

Sunset

Big Job #1: Landscape to Fight the Fire

1992

Lane Magazine and Book Company, June

Defines highly flammable plants as those that are accumulators of fuel, not maintained or pruned periodically, and contain high oil, high resin or low moisture in leaves and branches.

5

Sunset

Brush Clearing for Fire Safety

1968

Lane Magazine and Book Company, October

Describes fire retardant plants as those that are low-growing shrubs, non-native brush, and well maintained and watered brush.

6

California State Fire Marshal Journal

Landscape for Home Fire Safety

1989

CSFM Journal, No. 2, March/April

Defines flammable vegetation as plants containing volatile resins, oils, gums and terpenes, and plants that have accumulations of dead twigs and branches on mature live plants. This reference also defines fire retardant plants as those with a high moisture content, high in ash, well irrigated, free of dead matter, and low volume shrubs.

7

City of Los Angeles, Department of Arboreta & Botanic Gardens

Green Belts for Brush Fire Protection and Soil Erosion Control in Hillside Residential Areas

Date Unknown

City of Los Angeles, Dept. of Arboreta & Botanic Gardens, Arcadia, CA

The term fire retardant is used to describe plants inherently less flammable than others. Rates plants as HIGH(greatest fire retardance) low-growing succulent plants with thick, fleshy leaves and/or stems. MODERATE(moderate fire retardance) low-growing herbaceous perennials and sub-shrubs not distinctly succulent. LOW(low fire retardance) low-growing shrubs and sub-shrubs with rather dry, leathery or rigid leaves and branches.

8

East Bay Municipal Utility District Water Conservation Division

Firescape: Landscaping to Reduce Fire Hazard

1995

Community Services Department and EBMUD Board of Directors

Defines flammable or hazardous vegetation as any vegetation, including ornamental, that either by it's intrinsic characteristics, placement, or lack of care is easy to ignite, spreads fire rapidly, produces high heat, or creates fires that are difficult to suppress. Defines a fire resistant plant as less likely to burn, grows close to the ground and takes longer to ignite.

9

Brende and Shapiro Tree And Shrub Care

List of More and Less Fire Prone Plants

Date Unknown

Brende and Shapiro Tree and Shrub Care, Berkeley, CA

This reference suggests that any plant can be fire-prone if not properly maintained. Arrangement, spacing, density and dryness of the vegetation is probably more crucial than what species are planted.

10

Gilmer, Maureen

California Wildfire Landscaping

1994

Taylor Publishing Company, Dallas, TX

Plants are grouped as the most fire retardant if they retain high levels of moisture in their leaves and stems; these plants are mostly succulents and have low-growth habits. Moderate fire retardance is given to plants that are non-succulent with leaves that retain a high moisture content. Plants with low fire retardance are those with leathery and dry leaves.

11

California Department of Forestry and Fire Protection

Fire-Safe Demonstration Garden

Date Unknown

Santa Clara Ranger Unit

A list of plants is offered without definition of fire retardance.

12

Berkeley Horticulture Nursery

Fire Resistant Plants

1991

Berkeley Horticulture Nursery, Berkeley, CA

Defines fire resistant as being able to withstand high temperatures for prolonged periods without igniting and does not readily support open flames.

13

Maire, Richard G.

Landscape to Prevent Fire

1962

University of California Agricultural Extension Service

Fire retardance is not defined in this publication.

14

Northeast Ridge, Southwest Diversified

Final Habitat Fire Buffer Program

1990

Northeast Ridge, Brisbane, CA, Southwest Diversified, INC.

This reference states that all plants will burn under the worst conditions, but some are more suitable for fire-prone areas because of one or more of the following characteristics: high mineral content, high moisture content, low volume of fuel.

15

D'Alcamo, Susan; Rice, Carol L.

Appropriate Landscaping Plants to Reduce Fire Hazard

Date Unknown

East Bay Chapter, California Native Plant Society, Berkeley, CA

Supplies a list of California native plants to be used to establish a more fire retardant environment because of one or more of the following characteristics: high mineral content, low fuel volume, high moisture content.

16

Red Shingle & Handsplit Shake Bureau

The Green Fireman Plan

1988

Red Cedar Shingle & Handsplit Shake Bureau, Bellevue, WA

This references bases its recommendations of fire retardance on the following: plants with a high moisture content, low volume shrubs, and (up to a point) plants with a high ash content.

17

Phoenix Team of the Environmental Action Committee of West Marin

After the Vision Fire

1996

Phoenix Team of the Environmental Action Committee of West Marin

This reference provides a list of suggested fire retardant plants; fire retardant is not defined.

18

Morris, Wendy; Barbar, J.R.

Design and Siting Guidelines: Bush Fire Protection for Rural Houses

Date Unknown

Country Fire Authority, Victoria

This reference suggests that the degree of fire retardance of a tree or shrub depends on the amount of moisture in the leaves, the amount of oil or resin in the leaves, and/or the amount of dead matter that remains on the tree. Trees and shrubs were rated as follows: HIGH - most suitable; MODERATE - suitable. Groundcovers were rated as follows: HIGH - very succulent, MODERATE - semi-succulent.

19

Brush Fire Safety Committee

Make it Safe to Live in the Hills: Fire Resistant Plants

Date Unknown

Brush Fire Safety Committte, Los Angeles, CA

This reference explains that some plants are relatively non-flammable because they are able to withstand high temperatures for prolonged periods without igniting and do not readily support open flames.

20

Radtke, Klaus W.H.

A Homeowner's Guide to Fire and Watershed Management at the Chaparral/Urban Interface

1993

County of Los Angeles, CA

Fire retardance was rated as follows: HIGH - very highly fire retardant. MODERATE - medium fire retardance. LOW - low very retardance.

21

Radtke, Klaus W.H.

Living More Safely in the Chaparral/Urban Interface

Date Unknown

U.S. Dept. of Agriculture, Pacific Southwest Forest and Range Experimant Station, Gen.Technical Report PSW-67

Fire retardance was rated as follows: HIGH - very highly fire retardant. MODERATE - medium fire retardance. LOW - low very retardance.

22

Maire, Richard G.; Goodin, J.R.

Landscape for Fire Protection

1969

University of California Agricultural Extension Service

Refers to Los Angeles Arboretum research. Makes clear the point that the term "fire resistant" is used, but that there is not a plant that exists that will not burn given the right conditions. Also suggests that well-maintained and well-watered plants will not burn as readily as those left dry and unmaintained.

23

Grounds Maintenance

Flirting With Fire

1988

Grounds Maintenance, August 23(8):32,36,38,104.

Erosion control was rated as : LOW - 30% or less. MODERATE - 60%. HIGH - 60% or steeper.

24

County of Los Angeles Arboreta & Botanical Gardens

Fire Retardant Plants for Hillside Areas

1970

County of Los Angeles Arboreta and Botanical Gardens, Los Angeles, CA

Bases fire retardance on relatively high moisture content and prostrate or creeping growth characteristics. Rated as follows: HIGH - succulents (90-95% moisture content). MODERATE - non-succulents(80-95% MC) or 70-80% MC. LOW - 60-75% MC.

25

Santa Barbara City Fire Department

Firescape Demonstration Garden

Date Unknown

Santa Barbara City Fire Department, Santa Barbara, CA.

This reference offers only a list of suggested fire retardant plants, no criteria are given.

26

Coate, Barrie

Water-Conserving Plants and Landscapes for the Bay Area

1990

East Bay Municipal Utility District

Only offers a list of plants considered to be more fire retardant than most plants. No criteria offered.

27

Rice, Carol

Effects of Drought on Landscaping in the Paint Fire

1991

Wildland Resource Management, Walnut Creek, CA

Lists species with the highest moisture content and therefore probably the most fire retardant. Also lists the driest plants -- these were classified as not being recommended for fire prone areas.

28

City of San Carlos

Fire Resistive Plants

1996

The City of San Carlos, CA

Gives a list of herbaceous perennials, succulents, trees and groundcovers considered to be fire retardant. No definition offered.

29

Beatty, Russell

Designing Gardens for Fire Safety

1991

Department of Landscape Architecture, University of California, Berkeley

Rates plants fire retardance based on the following: Broad-leafed plants tend to be more fire retardant than those with needle-like or very fine leaves; dense compact forms and low prostrate plants are more effective at retarding fire than more open or upright plants.

30

Harlass, Sherry

How to Firescape to Reduce the Fire Hazard

1993

Nursery Manager, December

Defines a fire retardant plant as one that burns slowly.

31

Orinda Fire Protection District

Protect Your Home: Landsape For Fire Protection

Date Unknown

Orinda Fire Protection District

Offers a few fire retardant landscape plants with no criteria for classifying them as such.

32

California Department of Forestry

Fire Safe, California!

Date Unknown

California Department of Forestry and Fire Protection, Sacramento, CA

Classifies fire retardant plants as those that are hardy succulents and flat ground covering plants that are kept groomed and free of dry leaves.

33

City of Santa Barbara Fire Department

City of Santa Barbara Firescapes Demonstration Garden

Date Unknown

City of Santa Barbara Fire Department, Santa Barbara, CA

Defines fire resistant plants as those plants that can regenerate growth, despite burning and fire retardant plants as those which are less flammable than others.

34

Bowker, Mike

High Danger this Year: Preventing the Firestorm

1995

Motorland/CSAA, July/August

Considers that fire retardant plants share the following characteristics: grow close to the ground, have a low sap or resin content, grow without accumulating dead matter, are easily maintained and pruned, and are often drought tolerant.

35

South County Fire

Protecting Your Home From a Brush Fire

Date Unknown

South County Fire

Offers only a list of plants, without explanation or definition.

36

Sunset

Protecting Your Home Against Brushfire

1983

Lane Publishing Company

Lists succulents as having the greatest fire retardance. Herbaceous perennials if well-watered and woody groundcovers if well-watered are also highly recommended.

37

Department of Water Resources, The Resources Agency

Plants for California Landscapes: A Catalog of Drought Tolerant Plants

1979

State of California, The Resources Agency, Department of Water Resources, Bulletin 209, September

Offers a list of recommended plants without explanation or definition.

38

LeMay, David B; Wayne G. Mitchell

Recommended Low-Fuel Volume Species for San Luis Obispo County

1978

San Luis Obispo, CA: Central Coast Fire Prevention Association

Rates species of plants as either having HIGH/MODERATE or LOW fire retardance; no explanation or definition of terms.

39

Martin-Richardson, Brenda; San Luis Obispo County Fire Department

A Homeowner's Guide to Fire Resistant Plants for the San Luis Obispo Area

Date Unknown

San Luis Obispo, CA: CA Dept. of Forestry & Fire Protection and The San Luis Obispo County Fire Dept.

Lists fire retardant plants for the San Luis Obispo area; no criteria offered.

40

Moritz, Ray; Pavel Svihra

Pyrophytic vs. Fire Resistant Plants

1996

University of California Cooperative Extension HortScript February No. 18

Defines fire resistant as: most broad leaf deciduous trees; leaves tend to be supple, moist and easily crushed; trees tend to be clean, not bushy, and have little deadwood; shrubs are low-growing (<2') with minimal dead material; tall shrubs are clean, not bushy; sap is water-like and typically does not have a strong odor; and plants that will not sustain a flame when ignition is attempted.

41

Moritz, Ray

Pyrophytic vs. Fire Resistant Plants

1995

San Rafael Fire Department, FireSafe Marin. May

Defines fire resistant as: most broad leaf deciduous trees; leaves tend to be supple, moist and easily crushed; trees tend to be clean, not bushy, and have little deadwood; shrubs are low-growing (<2') with minimal dead material; tall shrubs are clean, not bushy; sap is water-like and typically does not have a strong odor; and plants that will not sustain a flame when ignition is attempted.

42

Perry, Bob

Trees and Shrubs for Dry California Landscapes

1989

Land Design Publishing, Claremont, CA

Fire retardance was rated as follows: LOW - high fire hazard species and undesirable domestic plant. MODERATE - acceptable domestic plant that requires ample amounts of water for best performance and valuable watershed species that should be thinned to reduce foliage mass, and be retained in limited numbers to prevent high intensity fires. HIGH - low-growing and high fire retarding plants and low fuel volume native and introduced species.

43

Ellefson, Connie Lockhart; Thomas L. Stephens; Doug Welsh, Ph.D.

Xeriscape Gardening

1992

Macmillian Publishing Company, New York

Offers plant lists only with no definition of drought or drought tolerance.

44

Brenzel, Kathleen Norris (editor)

Sunset Western Garden Book

1995

Menlo Park, CA: Sunset Publishing Corporation, March

This reference was used to gather mature plant characterisitics and information on drought tolerance, climate zones and erosion control. Drought tolerance is defined as requiring little or no dry season water. Climate zones are defined for the western states, each species is listed with a list of zones that it will tolerate. The zone map for this publication was generated from Sunset Western Garden Book's climate zone information. Note is made if a plant is considered to be useful in erosion control, but further explanation is not offered.

45

U.S. Dept. of Agriculture, Soil Conservation Service, Davis, CA

Plant Materials Study

1976

U.S Dept. of Agriculture, Soil Conservation Service, Davis, CA

Offers information on plants suitable for erosion control.

46

Deering, Robert Bowman

A Study of Drought Resistant Ornamental Plants

1955

Davis, CA: University of California, Davis

Offers plant lists only with no definition of drought or drought tolerance.

47

International Erosion Control Association

Proceedings of International Erosion Control Association, 8th Conference

1977

Seattle, WA: The Association. Feb 24-25, 1977, Airport Marina Hotel, Burlingame, CA.

Offers species recommended for erosion control without providing a rating or a definition.

48

Edmuson, George C.

Plant Materials Study: A Search for Drought-Tolerant Plant Materials for Erosion Control, Revegetation and Landscaping along California Highways: Final Report

1976

U.S Dept. of Agriculture, Soil Conservation Service, Davis, CA

Offers plant lists only with no definition of drought or drought tolerance.

49

Resource Management International, Inc.

Windbreaks Demonstration Project: Final Report

1988

Sacramento, CA: The Office of Land Conservation, California Department of Conservation

Offers plant lists only with no definition of drought or drought tolerance.

50

Lenz, Lee W.; Dourley, John

California Native Trees And Shrubs

1981

Rancho Santa Ana Botanic Garden, Claremont, CA

Offers plant lists only with no definition of drought or drought tolerance.

51

Nehrling, Arno; Irene Nehrling

Easy Gardening with Drought-Resistant Plants

1975

New York: Dover Publications, Inc.

Defines drought as less than 1" of rainfall/week or </= 20" for growing season. Plants considered drought tolerant will survive under these conditions.

52

Hazlewood, Walter G.

A Handbook of Trees, Shrubs, and Roses

1968

Sydney, Australia: Angus & Robertson, LTD

Defines drought tolerant plants as those recommended for "hot, dry areas where they will not get any watering."

53

Orange County Fire Department

Report of the Wildland/Urban Interface Task Force

1994

Developed by the Orange County Wildland/Urban Interface Task Force Subcommittee on Fuel Modification. July Attachment C

Defines plants that are not suitable for fire prone areas as possessing some or all of the following characteristics: are known to be especially combustible; have dry or deciduous foliage during part of the year; develop deciduous or shaggy bark; develop dry or dead undergrowth.

54

Perry, Bob

Landscape Plants for Western Regions: An Illustrated Guide to Plants for Water Conservation

1992

Claremont, CA : Land Design Publishing

Categorizes landscape plants based on the water needs. Also provides information on the mature characteristics of plants.

55

Hickman, James C. (editor)

The Jepson Manual: Higher Plants of California

1993

University of California Press, Berkeley and Los Angeles, CA

Provides information on plant classification and mature plant characteristics.

56

The Staff of the Liberty Hyde Bailey Hortorium, Cornell University

Hortus Third: A Concise Dictionary of Plants Cultivated in the United States and Canada

1976

New York, NY: MacMillan Publishing Company, Inc.

Provides detailed information on mature plant characteristics.

57

Costello, L.R.; K.A. Jones

Water Use Classification of Landscape Species: A Guide to the Water Needs of Landscape Plants

1994

Half Moon Bay, CA: University of California Cooperative Extension, San Mateo/San Francisco Counties

Provides recommended watering for over 1200 landscapes plants based on 6 climate regions of California.

 

Landscape Vegetation Database

This is the master list of vegetation information which includes mature plant characteristics, climate zones, drought resistance and erosion control recommendations. The drought resistance information is included because the vigor of the plant is compromised and the amount of dead material higher in plants that are stressed by drought, creating a greater than expected fire risk. Erosion control information is included because many high-fire hazard zones include steep slopes and the selection of plants needs to consider both fire performance and erosion control. If information on these characteristics was not available from the references used, it is so noted in the text. As the information becomes available, the database will be updated.

View the Plant Database - downloadable pdf file (Best viewed with Adobe Acrobat Reader)

 

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this page last revised 06.13.2000