U.S. Geological Survey

Southwest Biological Science Center

2255 N. Gemini Drive

Flagstaff, AZ 86001
Other than this note, this page intentionally left blank.
In cooperation with University of Arizona, Cooperative Extension and School of Natural Resources 

Southwest Exotic Mapping Program 2007: 

Occurrence Summary and Maps of Select Invasive, 

Non-native Plants in Arizona 

By Kathryn A. Thomas and Patricia Guertin 

Open-File Report 2007-1277 

October 2007 

U.S. Department of the Interior 

U.S. Geological Survey 

 

U.S. Geological Survey 

Southwest Biological Science Center 

Sonoran Desert Research Station 

University of Arizona 

School of Natural Resources 

125 Biological Sciences East 

Tucson, Arizona 85721 
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark Myers, Director 

U.S. Geological Survey, Reston, Virginia: 2007 

For product and ordering information: 

World Wide Web: http://www.usgs.gov/pubprod

Telephone: 1-888-ASK-USGS 

For more information on the USGS-the Federal source for science about the Earth, its 

natural and living resources, natural hazards, and the environment: 

World Wide Web: http://www.usgs.gov

Telephone: 1-888-ASK-USGS 

 

Suggested Citation 

Thomas, K.A., and P. Guertin. 2007, Southwest Exotic Mapping Program 2007; 

occurrence summary and maps of select invasive, non-native plants in Arizona: U.S. 

Geological Survey Open-File Report 2007-1277 [http://pubs.usgs.gov/of/2007/1277/]. 

Cover: Design by Patricia Guertin, Southwest Biological Science Center. Salsola tragus

skeletons on sand dune at Petrified Forest National Park, Arizona. 

Any use of trade, product, or firm names is for descriptive purposes only and does not 

imply endorsement by the U.S. Government. 

ii 
Authors 

Kathryn A. Thomas and Patricia Guertin 

USGS SBSC Sonoran Desert Research Station 

125 Biological Sciences East, Building 43 

The University of Arizona 

Tucson, AZ 85721 

U.S. Geological Survey SBSC Sonoran Desert Research Station Personnel 

Charles van Riper III, Station Leader 

William L. Halvorson, Research Ecologist 

Cecil R. Schwalbe, Ecologist 

Michael R. Kunzmann, Ecologist (Emeritus) 

Kathryn Thomas, Ecologist 

Pamela Nagler, Physical Scientist 

Phil Rosen, Ecologist 

Program and Expertise Areas of USGS and UA Personnel 

Avian Ecology 

Data Management 

Amphibian and Reptile Ecology 

Fire Management 

Global Climate Change 

Invasive Species Research 

Inventory and Monitoring 

Vegetation Mapping and Ecology 

USGS Southwest Biological Science Center http://sbsc.wr.usgs.gov

USGS Southwest Biological Science Center, Sonoran Desert Research Station http://sbsc.wr.usgs.gov/sdrs

iii 
Table of Contents 

Introduction .....................................................................................................................................1

Invasive plants in Arizona ..................................................................................................................1

SWEMP07 as a data source ...........................................................................................................1

Summary of Arizona invasive plants in SWEMP07...................................................................2

Occurrence maps.............................................................................................................................3

Use and limitations of this information............................................................................................6

For more information..........................................................................................................................6

References .....................................................................................................................................7

List of Tables and Figures 

Table 1. Top twenty invasive plant species in Arizona as identified by number of 

occurrence records in the SWEMP07 database. .........................................................................3

Table 2. Life form distribution of invasive plants in Arizona ................................................3

Table 3. Ranking systems for invasive plants.............................................................................4

Figure 1. Cooperative weed management areas.........................................................................5

List of Appendices 

Appendix I Invasive plants in Arizona as identified in the SWEMP07 database.................9

Appendix II Maps of select invasive plants in Arizona ...........................................................13

 

 Acroptilon repens...... ...........................................................................15 

 Ailanthus altissima..............................................................................16 

 Alhagi maurorum...... ..........................................................................17 

 Arundo donax......... ..........................................................................18

 Asphodelus fistulosus.............................................................................19

 Avena fatua......................................................................................20

 Brassica tournefortii...... .........................................................................21

 Bromus diandrus......... .........................................................................22

 Bromus inermis...................................................................................23

 Bromus rubens....................................................................................24

 Bromus tectorum............ ....... ...............................................................25

 Cardaria draba..................... ...............................................................26

 Carduus nutans............ ........ ...............................................................27

 Centaurea diffusa.................. ...............................................................28

 Centaurea melitensis...............................................................................29

 Centaurea solstitialis..............................................................................30

 Centaurea stoebe ssp. micranthos........ .........................................................31

 Centaurea virgata ssp. squarrosa...... ...........................................................32

 Chondrilla juncea..................... ............................................................33

 Cirsium arvense........................ ........ ...................................................34

 Cirsium vulgare........................ ........ ...................................................35

 Conium maculatum.................................................................................36

 Convolvulus arvensis........................... ...................................................37

iv 
 Cortaderia selloana.................................................. ..............................38

 Cynodon dactylon..................................................................................39

 Cynoglossum officinale............................................................................40

 Dipsacus fullonum....................................... ........................................41

 Eichhornia crassipe....................................... .........................................42

 Elaeagnus angustifolia.................................... .........................................43

 Elymus repens.......................................... ............................................44

 Eragrostis lehmanniana...........................................................................45

 Euphorbia esula...................................................................................46

 Euryops multifidus.................................... ... .......................................47

 Halogeton glomeratus.............................................................................48

 Hordeum murinum................................................................................49

 Hydrilla verticillata................................................................................50

 Lepidium latifolium....................................... ........................................51

 Leucanthemum vulgare.............................................. ..............................52

 Linaria dalmatica................................................................................53

 Lolium perenne.....................................................................................54

 Melilotus officinalis....................................... .........................................55

 Mesembryanthemum crystallinum.................................................................56

 Mesembryanthemum nodiflorum........................... ........................................57

 Myriophyllum aquaticum...........................................................................58

 Onopordum acanthium............................................................................59

 Pennisetum ciliare....................................... .........................................60

 Pennisetum setaceum................................................................................61

 Phleum pratense...................................................................................62

 Potentilla recta......................................................................................63

 Rhus lancea............................................. .............. ..............................64

 Rubus armeniacus................................................................................65

 Saccharum ravennae.................................... ..........................................66

 Salsola collina/tragus.................................... ........................................67

 Salvinia molesta.......................................... .........................................68

 Schismus arabicus/barbatus.......................................................................69

 Sonchus asper.......................................................................................70

 Sonchus oleraceus....................................... ..........................................71

 Sorghum halepense....................................... ........................................72

 Taeniatherum caput-medusae.............................. ........................................73

 Tamarix chinensis/parviflora/ramosissima..................... ...................................74

 Ulmus pumila................................................... .......... ........................75

 Verbascum thapsus................................................................................76

v 
1 

Introduction

An important aspect of management of invasive, non-native plants (invasive plants) is information 

on the type, location, and magnitude of infestations. Regional development of this information 

requires an integrated program of data collection, management, and delivery. The Southwest Exotic 

Plant Mapping Program (SWEMP), coordinated through the U.S. Geological Survey’s Southwest 

Biological Science Center, annually compiles occurrence records for infestations of invasive plants. 

Operating since 1998, the SWEMP team has accepted occurrence records contributed voluntarily by 

federal, tribal, state, and private collaborators and has compiled these contributions accumulatively 

with previous versions of SWEMP. The SWEMP 2007 regional database update, SWEMP07, 

contains 62,000 records for 221 plant species with records dating as far back as 1911 and up to 

December, 2006. Records include invasive plants in Arizona, eastern California, Colorado, New 

Mexico, and Utah. SWEMP07 is available through the Southwest Exotic Plant Information 

Clearinghouse (http://sbsc.wr.usgs.gov/research/projects/swepic/swepic.asp, click SWEMP). 

Not all invasive plants are non-native and not all invasive plants are even invasive. The 

Arizona Invasive Species Advisory Council (2006) defined an invasive species as “a species that is 

(1) non-native to the ecosystem under consideration and, (2) whose introduction causes or is likely 

to cause economic or environmental harm, or harm to human health”. SWEMP uses the U.S. 

Department of Agriculture PLANTS database (http://plants.usda.gov/) to determine if a plant is 

native or not to Arizona. As SWEMP does not independently assess the current or potential impact 

of invasive plants, we include most non-native plant records contributed. We have not included 

agricultural crops that are non-native, for example apples, oranges, etc. 

In this open-file-report, we use the SWEMP07 update to summarize the occurrence of 

invasive plants in Arizona and present distribution maps for a select invasive plants in Arizona. We 

use the word occurrence purposefully instead of the word distribution. The SWEMP07 database 

only provides an estimate of the actual distribution of invasive plants in Arizona. The information 

provided is a first approximation of the state-wide extent of invasive plant distribution. 

Invasive plants in Arizona 

SWEMP07 as a data source 

SWEMP07 was compiled from contributed occurrence records added to the SWEMP06 regional 

database. Not all contributed data is automatically added to the SWEMP database. In order for a 

species to be included, it must be listed as non-native in the Southwest by the PLANTS database. It 

must be submitted with proper geographic coordinates. All infestations of an invasive species 

found within one-hundred meters of an infestation of the same species in the same year are 

considered a single infestation. When this occurs the records are combined in the database as a 

single infestation. Taxonomic accuracy of the invasive plant record is the responsibility of the 

submitter. SWEMP07 records the submitter for each record and updates the infestation record if the 

taxonomy of the invasive plant needs correction. 

We emphasize that SWEMP07 does not represent a complete or systematic survey of 

invasive plants in Arizona and the Southwest. Submitted data may represent area surveys for a 

single species or for all non-native species. The surveys may have been restricted to certain features, 

such as along roadsides or in a disturbed area, such as a utility corridor. Areas that were surveyed 
2 

for which invasive species were absent are not incorporated into SWEMP07. In addition, SWEMP 

is an accumulative database, so presence in SWEMP07 indicates that the invasive species has been 

found at least once at the location, but not necessarily recently. The invasive plant may have been 

adequately managed and may no longer be present at the location. While submitters are asked to 

also indicate the size of the infestation, infestation size is still inconsistently reported. Also, as 

contributions are voluntary, the number of infestations does not necessarily indicate more of a 

problem in one area than other. Rather, a higher number of reported occurrences may indicate more 

dedicated collection effort in that area.

Summary of Arizona invasive plants in SWEMP07 

The infestation records for Arizona were subset from the SWEMP07 regional database. This subset 

contained 38,801 records for at least 149 species. Several species were grouped where 

differentiation between the species is difficult: Salsola collina and S. tragus; Schismus arabicus and 

S. barbatus; and Tamarix chinensis, parviflora, and ramosissima. Several genera included counts of 

invasive plants identified only to the genus level; these were removed from the summaries 

presented below (238 records total). 

Pennisetum ciliare (buffelgrass) had the most records; this invasive plant has been 

aggressively tackled by the Pima-Santa Cruz River Basin weed management area and other 

concerned agencies and public in southern Arizona. Salsola collina and tragus, Russian thistle, has 

the second most records. The high number of records for Russian thistle in part reflects many 

occurrence records contributed from an intensive survey conducted at Petrified Forest National 

Park. The top 20 invasive plant species or species groups constitute nearly 80% of all the SWEMP 

records for Arizona (Table 1). Sixty-seven species occur with 10 or fewer records; fifteen of these 

with only one observances. 

While all major lifeforms are represented in the records, most invasive plant records are 

either forbs or grasses (Table 2). There are slightly more records of invasive plants with perennial 

and biennial lifeforms (18,980 perennial and 3,544 biennial records) than annual (16,039 records). 

A summary of the species and species groups in the Arizona subset of the SWEMP2007 database is 

provided in Appendix I. 
3 

Table 1. Top twenty invasive plant species in Arizona as identified by number of occurrence 

records in the SWEMP07 database. 

Scientific Name Common Name Number 

of 

Records 

% of all 

records 

Pennisetum ciliare buffelgrass 6287 16.3% 

Salsola (collina, tragus) Russian thistle 3149 8.2% 

Tamarix (chinensis/parviflora/ramosissima) tamarisk 3027 7.8% 

Bromus tectorum cheatgrass 2013 5.2% 

Verbascum thapsus common mullein 1510 3.9% 

Linaria dalmatica dalmatian toadflax 1502 3.9% 

Erodium cicutarium redstem stork's bill 1439 3.7% 

Brassica tournefortii Asian mustard 1261 3.3% 

Cirsium vulgare bull thistle 1195 3.1% 

Alhagi maurorum camelthorn 1181 3.1% 

Bromus rubens red brome 1152 3.0% 

Pennisetum setaceum crimson fountaingrass 999 2.6% 

Eragrostis lehmanniana Lehmann lovegrass 980 2.5% 

Convolvulus arvensis field bindweed 922 2.4% 

Schismus (arabicus/barbatus) Mediterranean grass 919 2.4% 

Melilotus officinalis yellow sweetclover 869 2.3% 

Cynodon dactylon Bermudagrass 673 1.7% 

Marrubium vulgare horehound 594 1.5% 

Acroptilon repens hardheads 589 1.5% 

Onopordum acanthium Scotch cottonthistle 478 1.2% 

 79.7% 

 Table 2. Life form distribution of invasive plants in Arizona 

 as identified by number of occurrence records in the 

 SWEMP07 database. 

Number of 

Records 

 Lifeform 

16,678 Forb/herb 

15,808 Graminoid 

 1,838 Shrub/subshrub 

 3,545 Tree/ Shrub 

 932 Vine 

Occurrence maps 

We selected 62 invasive plants from the Arizona subset of the SWEMP2007 database that had 

moderate to high ratings as assigned by the Arizona Wildlands Invasive Plant Working Group, 

CAL-IPC, or NatureServe (Table 3) to present as maps (see Appendix II). Other species not 

included in the maps may also have severe to substantial impacts ecological impacts and species 

currently not rated as having moderate to high impact might actually have high impact locally. 
4

For each weed species three maps are presented, categorized by the number of observation 

records for that species. The maps are organized by 1) county, 2) weed management area, and 

3) 30 minute topographic quads. These different views of infestation patterns are complementary. 

Within Arizona, the last decade has seen the organization of weed management areas. 

Governmental, tribal, and private land managers and decision makers have partnered geographically 

to plan and act on their collective weed problems. The map of weed management areas, as known in 

the spring of 2007, was developed by the SWEMP team with information provided by each weed 

management area and shows the areas of concern for 13 weed management areas (Figure 1). The 

boundaries presented may be updated and revised by each weed management area at any time.

Table 3. Ranking systems for invasive plants. 

Ranking 

System Documentation Categories Summarized Meaning

Arizona legal Prohibited, regulated, and 

restricted noxious weeds (Plant 

Services Division 2005)

Prohibited ..prohibited from entry into the state

Regulated ..if found in the state may be controlled or 

quarantined to prevent further infestation or 

contamination

Restricted ..if found within the state shall be quarantined to 

prevent further infestation or contamination

AZ-WIPG Invasive Non-native Plants that 

Threaten Wildlands in Arizona 

(AZ-WIPG 2005)

High ..species have severe ecological impacts

Medium ..species have substantial and apparent ecological 

impacts

Low ..species have minor yet detectable ecological 

impacts

Alert ..additional designation for some species in either 

the high or medium category, but whose current 

ecological amplitude and distribution are limited

Red flag ..additional designation ..to identify and document 

a critical piece of information not evident in the 

overall ranking

Cal-IPC California Invasive Plant 

Inventory (Cal-IPC 2006)

High ..species have severe ecological impacts

Moderate ..species have substantial and apparent – but 

generally not severe – ecological impacts

Limited ..species are invasive but their ecological impacts 

are minor ...or not enough information 

NatureServe An Invasive Species Assessment 

Protocol (Morse et al 2004)

High ..species represents a severe threat to native species 

and ecological communities

Medium ..species represents moderate threat to native 

species and ecological communities
 Figure 1. Cooperative weed management areas. 

5 
6

Use and limitations of this information

The SWEMP occurrence records provide information that can help with invasive plant 

management, scientific studies on invasive plants, and as input toward development of more 

comprehensive development of invasive plant distribution collection.

• The invasive species listed give an overview of invasive plants that have been found in 

Arizona. 

• The identity of the invasive plants listed is the responsibility of the record provider. Some 

species may be misidentified at some locations. Field verification of the invasive plants 

identity is encouraged if management actions or policy decisions require high data accuracy.

• The lack of an occurrence record of an invasive plant in a weed management area, county or

30’ topo quad does not mean the invasive plant is not present. The invasive species listed 

indicate those invasive plants that have been documented. Surveys are limited in size and 

may include only those invasive plants the observer noticed. Invasive plants with small 

infestation sizes and new invasive plants that are not commonly known are often not 

documented.

• The maps do not indicate the actual intensity of infestation; they indicate the level of field 

survey effort and contribution to SWEMP07.

• The impact ratings provided for the mapped invasive species are based on what is know 

about those plants impacts on a state or national level. The plant may behave differently at a 

local site. Not all invasive plants that occur on the SWEMP07 listing have been assessed for 

impact at the state or national level.

• The SWEMP07 database contains historic records. Historical records are included in the 

summary and maps.

• Several mapped invasive plants have few occurrence records yet have been rated to have 

high impact. These invasive plants are candidates for vigorous early detection and rapid 

response in order to contain infestation within the state.

For more information

• Arizona Wildlands Invasive Plants: 

http://sbsc.wr.usgs.gov/research/projects/swepic/SWVMA/sbscmain.asp

• Arizona Invasive Species Advisory Council: http://www.governor.state.az.us/ais/

• California Invasive Plant Council (Cal-IPC): http://www.cal-ipc.org/

• Encycloweedia: http://www.cdfa.ca.gov/phpps/ipc/encycloweedia/encycloweedia_hp.htm

• The National Institute of Invasive Species Science: http://www.niiss.org

• NatureServe Explorer: http://www.natureserve.org/explorer/

• NBII Invasive Species: http://invasivespecies.nbii.gov/

• Southwest Exotic Plant Information Clearinghouse: 

http://sbsc.wr.usgs.gov/research/projects/swepic/swepic.asp

• USDA PLANTS Database: http://plants.usda.gov

• USDA PLANTS Invasive and Noxious Weeds: http://plants.usda.gov/java/noxiousDriver
7 

References 

Arizona Invasive Species Advisory Council. 2006. Arizona’s Invasive Species: A Report to the 

Governor. Available at: 

http://www.governor.state.az.us/ais/Documents/Final%20Invasive%20Report%20low%20res.pdf. 

Arizona Wildlands Invasive Plant Working Group. 2005. Invasive Non-Native Plants that Threaten 

Wildlands in Arizona. Available at: 

http://sbsc.wr.usgs.gov/research/projects/swepic/SWVMA/InvasiveNonNativePlantsThatThreatenWildlandsInArizona.pdf 

Cal-IPC. 2006. California Invasive Plant Inventory. Cal-IPC Publication 2006-02. California 

Invasive Plant Council: Berkeley, CA. Available: http://www.calipc.org/ip/inventory/pdf/Inventory2006.pdf. Accessed June 2007. 

Morse, L.E., J.M. Randall, N. Benton, R. Hiebert, and S. Lu. 2004. An Invasive Species 

Assessment Protocol: Evaluating Non-Native Plants for Their Impact on Biodiversity. Version 1. 

NatureServe, Arlington, Virginia. Available at: 

http://www.natureserve.org/library/invasiveSpeciesAssessmentProtocol.pdf 

Plant Services Division. Prohibited, regulated and restricted noxious weeds. 2005. Arizona 

Department of Agriculture. Available at: http://www.azda.gov/PSD/quarantine5.htm. Accessed 

June 2007. 

Whitson, T.D. ed., L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee and R. Parker. 

2006. Weeds of the West 9th edition. The Western Society of Weed Science in cooperation with the 

Western United States Land Grant Universities Cooperative Extension Service. 
8 
9 

Appendix I Invasive plants in Arizona as identified in the 

SWEMP07 database 

Scientific Name Common Name Number 

of 

Records 

Lifeform Duration 

Acroptilon repens* hardheads 589 F P 

Aegilops cylindrica jointed goatgrass 3 G A 

Agropyron desertorum desert wheatgrass 43 G P 

Ailanthus altissima* tree of heaven 29 T P 

Alhagi maurorum* camelthorn 1181 S P 

Amaranthus blitoides mat amaranth 2 F A 

Apium graveolens wild celery 1 F P 

Arctium minus lesser burdock 6 F B 

Arundo donax* giant reed 12 G P 

Asphodelus fistulosus* onionweed 6 F P 

Avena fatua* wild oat 379 G A 

Azolla pinnata pinnate mosquitofern 2 F A 

Bassia scoparia burningbush 324 F A 

Brassica nigra black mustard 1 F A 

Brassica tournefortii* Asian mustard 1261 F A 

Bromus arvensis field brome 30 G A 

Bromus berteroanus Chilean chess 9 G A 

Bromus catharticus rescuegrass 30 G A, P 

Bromus diandrus* ripgut brome 146 G A, P 

Bromus inermis* smooth brome 113 G P 

Bromus racemosus bald brome 1 G A 

Bromus rubens* red brome 1152 G A 

Bromus tectorum* cheatgrass 2013 G A 

Caesalpinia gilliesii bird-of-paradise shrub 1 T P 

Capsella bursa-pastoris shepherd's purse 3 F A 

Cardaria draba* whitetop 9 F P 

Carduus acanthoides spiny plumeless thistle 6 F B 

Carduus nutans* nodding plumeless thistle 187 F B, P 

Centaurea diffusa* diffuse knapweed 318 F A, P 

Centaurea melitensis* Maltese star-thistle 303 F A, B 

Centaurea solstitialis* yellow star-thistle 94 F A 

Centaurea stoebe ssp. micranthos* spotted knapweed 76 F B, P 

Centaurea virgata ssp. squarrosa* squarrose knapweed 3 F P 

Ceratocephala testiculata curveseed butterwort 7 F A 

Chenopodium album lambsquarters 1 F A 

Chenopodium murale nettleleaf goosefoot 23 F A 

Chondrilla juncea* rush skeletonweed 47 F P 

Chorispora tenella crossflower 12 F A 

Cichorium intybus chicory 13 F B, P 

Cirsium arvense* Canada thistle 6 F P 

Cirsium vulgare* bull thistle 1195 F B 

Conium maculatum* poison hemlock 10 F B 

Convolvulus arvensis* field bindweed 922 V P 

Cortaderia selloana* Uruguayan pampas grass 8 G P 
10 

Scientific Name Common Name Number 

of 

Records 

Lifeform Duration 

Cynodon dactylon* Bermudagrass 673 G P 

Cynoglossum officinale* gypsyflower 21 F B 

Cyperus esculentus yellow nutsedge 31 G P 

Dactylis glomerata orchardgrass 90 G P 

Dactyloctenium radulans buttongrass 7 G A 

Descurainia sophia herb sophia 295 F A, B 

Dimorphotheca sinuata glandular Cape marigold 10 F A 

Dipsacus fullonum* Fuller's teasel 2 F B 

Echinochloa colona jungle rice 17 G A 

Echinochloa crus-galli barnyardgrass 10 G A 

Eichhornia crassipes* floating water hyacinth 8 F P 

Elaeagnus angustifolia* Russian olive 400 T P 

Elymus repens* quackgrass 22 G P 

Eragrostis cilianensis stinkgrass 272 G A 

Eragrostis curvula weeping lovegrass 295 G P 

Eragrostis echinochloidea African lovegrass 6 G P 

Eragrostis lehmanniana* Lehmann lovegrass 980 G P 

Erodium cicutarium redstem stork's bill 1439 F A, B 

Eruca vesicaria rocketsalad 40 F A 

Erysimum repandum spreading wallflower 2 F A 

Euphorbia esula* leafy spurge 17 F P 

Euryops multifidus* hawk's eye 7 S P 

Halogeton glomeratus* saltlover 280 F A 

Hordeum murinum* mouse barley 239 G A 

Hordeum vulgare common barley 16 G A 

Hydrilla verticillata* hydrilla 9 F P 

Ipomoea hederacea ivyleaf morningglory 7 V A 

Ipomoea purpurea tall morningglory 2 V A 

Ipomoea tricolor multicolored morningglory 1 V A 

Lactuca serriola prickly lettuce 307 F A, B 

Lepidium latifolium* broadleaved pepperweed 45 F P 

Lepidium perfoliatum clasping pepperweed 1 F A, B 

Leucanthemum vulgare* oxeye daisy 3 F P 

Linaria dalmatica* dalmatian toadflax 1502 F P 

Lolium perenne* perennial ryegrass 2 G A, P 

Malcolmia africana African mustard 5 F A 

Malva neglecta common mallow 9 F A, B, P 

Malva parviflora cheeseweed mallow 77 F A, B, P 

Marrubium vulgare horehound 594 S P 

Medicago lupulina black medick 60 F A, P 

Medicago minima little burclover 2 F A 

Medicago polymorpha California burclover 2 F A, P 

Medicago sativa alfalfa 26 F A, P 

Melilotus indicus annual yellow sweetclover 55 F A 

Melilotus officinalis* yellow sweetclover 869 F A, B, P 

Melinis repens rose Natal grass 139 G A, P 

Mesembryanthemum crystallinum* common iceplant 3 F A, P 

Mesembryanthemum nodiflorum* slenderleaf iceplant 1 F A, P 

Morus alba white mulberry 1 T P 
11 

Scientific Name Common Name Number 

of 

Records 

Lifeform Duration 

Myriophyllum aquaticum* parrotfeather 1 F P 

Nerium oleander oleander 3 T P 

Nicotiana glauca tree tobacco 16 T P 

Onopordum acanthium* Scotch cottonthistle 478 F B 

Packera glabella butterweed 1 F A 

Panicum antidotale blue panicum 7 G P 

Paspalum dilatatum dallisgrass 2 G P 

Pennisetum ciliare* buffelgrass 6287 G P 

Pennisetum setaceum* crimson fountaingrass 999 G P 

Phalaris caroliniana Carolina canarygrass 1 G A 

Phalaris minor littleseed canarygrass 26 G A 

Phleum pretense* timothy 24 G P 

Phoenix dactylifera date palm 3 T P 

Plantago lanceolata narrowleaf plantain 1 F A, B, P 

Plantago macrocarpa seashore plantain 1 F P 

Poa annua annual bluegrass 2 G A 

Poa bulbosa bulbous bluegrass 5 G P 

Poa compressa Canada bluegrass 12 G P 

Poa pratensis Kentucky bluegrass 274 G P 

Polygonum aviculare prostrate knotweed 39 F A, P 

Polypogon monspeliensis annual rabbitsfoot grass 129 G A 

Polypogon viridis beardless rabbitsfoot grass 8 G P 

Potentilla recta* sulphur cinquefoil 3 F P 

Rhus lancea* African sumac 5 T P 

Rubus armeniacus* Himalayan blackberry 55 S P 

Rumex acetosa garden sorrel 8 F P 

Rumex crispus curly dock 35 F P 

Saccharum ravennae* ravennagrass 159 G P 

Salsola (collina/tragus)* Russian thistle 3149 F A 

Salvia aethiopis Mediterranean sage 32 F B 

Salvinia molesta* giant salvinia 321 F A, P 

Schedonorus phoenix tall fescue 2 G P 

Schismus (arabicus/barbatus)* Mediterranean grass 919 G A 

Setaria pumila ssp. pumila yellow foxtail 7 G A 

Setaria viridis green bristlegrass 5 G A 

Silene vulgaris bladder campion 6 F P 

Silybum marianum milk thistle 4 F A, B 

Sinapis arvensis wild mustard 5 F A 

Sisymbrium altissimum tall tumblemustard 147 F A, B 

Sisymbrium irio London rocket 401 F A 

Solanum nigrum black nightshade 1 S A, P 

Sonchus arvensis marsh sowthistle 4 F P 

Sonchus asper* spiny sowthistle 34 F A 

Sonchus oleraceus* common sowthistle 62 F A 

Sorghum halepense* Johnsongrass 185 G P 

Taeniatherum caput-medusae* medusahead 4 G A 

Tamarix aphylla Athel tamarisk 20 T P 

Tamarix (chinensis/parviflora/ramosissima)* tamarisk 3027 T P 

Taraxacum officinale common dandelion 114 F P 
12 

Scientific Name Common Name Number 

of 

Records 

Lifeform Duration 

Tragopogon dubius yellow salsify 194 F A, B 

Tribulus terrestris puncturevine 278 F A 

Trifolium repens white clover 22 F P 

Ulmus pumila* Siberian elm 40 T P 

Verbascum blattaria moth mullein 4 F B 

Verbascum thapsus* common mullein 1510 F B 

Verbascum virgatum wand mullein 4 F B 

 

1 Invasive plants in bold and with a * following the name are represented on a map in the Appendix. 

2

 Common names are from the PLANTS online database or from the Weeds of the West (Whitson 

et al 1992). 

3

 F=Forb/herb, G=Graminoid, S=Shrub/subshrub, T=Tree/tall shrub, V=Vine 

4

 P=perennial, B=biennial, A=annual 
13 

Appendix II Maps of select invasive plants in Arizona 
14 
15

 Acroptilon repens

Synonym: Centaurea repens

Common Name: Russian

knapweed,hardheads

USDAPlantCode: ACRE3

Family: Asteraceae 

Arizona legal listing: Prohibited ,

Regulated

AZ-WIPWGcategory: High

Cal-IPCcategory: Moderate

NatureServeranking: High

Map legend :

No records

1-10 records

11-100 records

101-1000 records

>1000 records

SWEMP occurrence recor ds by County

SWEMP occurrence records by

Weed ManagementArea SWEMP occurrence records by 

30’ Topographic Quadrangles
16 

 Ailanthus altissima

Synonym:

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

none

tree of heaven 

AIAL

Simaroubaceae

none

Medium

Moderate

Medium

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 
 Alhagi maurorum

Synonym: Alhagi pseudalhagi, 

Alhagi camelorum

camelthorn 

ALMA12

Fabaceae

Prohibited, 

Restricted

Medium

Moderate

Medium

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

17 
 Arundo donax

Synonym: none

giant reed 

ARDO4

Poaceae

none

High

High

High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

18 
 Asphodelus fistulosus

Synonym: none

onionweed, 

asphodelus 

ASFI2

Liliaceae

none

Low

Moderate - 

Alert

not assessed 

at present

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

19 
 Avena fatua

Synonym: none

wild oat 

AVFA

Poaceae

none

Medium

Moderate

Unknown

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

20 
 Brassica tournefortii

Synonym: none

African mustard, 

Asian mustard 

BRTO

Brassicaceae

none

Medium, 

Red flag

High

Unknown

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

21 
 Bromus diandrus

Synonym: Bromus rigidus var. 

gussonei

ripgut brome 

BRDI3

Poaceae

none

Medium - 

Alert

Moderate

not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

22 
 Bromus inermis

Synonym: none

smooth brome

BRIN2

Poaceae

none

Medium, 

Red Flag

not assessed at 

present

Medium

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

23 
 Bromus rubens

Synonym: Bromus madritensis ssp. 

rubens

red brome

BRRU2

Poaceae

none

High

High

not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

24 
 Bromus tectorum

Synonym: none

downy brome, 

cheatgrass

BRTE

Poaceae

none

High 

High 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

25 
 Cardaria draba

Synonym: none

whitetop

CADR

Brassicaceae

Prohibited, 

Restricted

Medium - 

Alert

Moderate

not assessed 

at present

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

26 
 Carduus nutans

Synonym: none

nodding 

plumeless thistle, musk thistle

CANU4

Asteraceae

none

Medium

Moderate

Unknown

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

27 
 Centaurea diffusa

Synonym: none

white knapweed, 

diffuse knapweed

CEDI3

Asteraceae

 Prohibited, 

Restricted 

Medium

Moderate

High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing:

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

28 
 Centaurea melitensis

Synonym: none

Maltese 

starthistle, Malta starthistle

CEME2

Asteraceae

none

Medium

Moderate

Medium

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

29 
 Centaurea solstitialis

Synonym: none

yellow starthistle

CESO3

Asteraceae

Prohibited, 

Restricted

High

High

High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

30 
 Centaurea stoebe ssp. micranthos

Synonym: Centaurea biebersteinii,

Centaurea maculosa

spotted knapweed

CESTM

Asteraceae

none

Medium, 

Red Flag

not assessed at 

present

High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

31 
 Centaurea virgata ssp. squarrosa

Synonym: Centaurea triumfettii, 

Centaurea virgata, Centaurea 

squarrosa

squarrose 

knapweed

CEVIS2

Asteraceae

Prohibited

not 

assessed at present

Moderate

Unknown 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

32 
 Chondrilla juncea

Synonym: none 

hogbite, rush 

skeletonweed 

CHJU

Asteraceae

Prohibited

Medium - 

Alert

Moderate

Unknown 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

33 
 Cirsium arvense

Synonym: none 

Canada thistle 

CIAR4

Asteraceae

Prohibited

Medium, 

Red Flag 

Moderate 

High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

34 
 Cirsium vulgare

Synonym: none

bull thistle 

CIVU

Asteraceae

none

Low

Moderate

Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking: 

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

35 
 Conium maculatum

Synonym: none

poison hemlock 

COMA2

Apiaceae

none

Medium - 

Alert 

Moderate 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

36 
 Convolvulus arvensis

Synonym: none

field bindweed 

COAR4

Convolvulaceae

Prohibited, 

Regulated

Medium 

Evaluated, Not 

Listed 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

37 
 Cortaderia selloana

Synonym: none

Uruguayan 

pampas grass, Selloa pampas grass 

COSE4

Poaceae

none

Medium, 

Red Flag 

High 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

38 
 Cynodon dactylon

Synonym: none

Bermudagrass 

CYDA

Poaceae

none

Medium 

Moderate 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

39 
 Cynoglossum officinale

Synonym: none

gypsyflower, 

houndstongue 

CYOF

Boraginaceae

none

Low 

Moderate 

 Medium 

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

40 
 Dipsacus fullonum

Synonym: none

Fuller's teasel 

DIFU2

Dipsaceae

none

not 

assessed at present 

Moderate 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

41 
 Eichhornia crassipes

Synonym: none

common water 

hyacinth 

EICR

Pontederiaceae

Prohibited, 

Regulated, Restricted

High - 

Alert, Red Flag 

High - Alert 

 High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

42 
 Elaeagnus angustifolia

Synonym: none

Russian olive 

ELAN

Elaeagnaceae

none

High 

Moderate 

 High

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

43 
 Elymus repens 

Synonym: Agropyron repens, 

Elytrigia repens

quackgrass 

ELRE4

Poaceae

none

Low 

not assessed at 

present 

 High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

44 
 Eragrostis lehmanniana 

Synonym: none

Lehmann 

lovegrass 

ERLE

Poaceae

none

High 

not assessed at 

present 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

45 
 Euphorbia esula 

Synonym: none

leafy spurge

EUES

Euphorbiaceae

Prohibited

High - 

Alert 

High - Alert 

 High

Common Name:

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

46 
 Euryops multifidus 

Synonym: Euryops subcarnosus

ssp. vulgaris

sweet resinbush 

EUMU

Asteraceae

Restricted

High, Red 

Flag 

not assessed at 

present 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

47 
 Halogeton glomeratus 

Synonym: none

saltlover, 

halogeton 

HAGL

Chenopodiaceae

Prohibited, 

Restricted

not 

assessed at present 

Moderate 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

48 
 Hordeum murinum 

Synonym: none

mouse barley 

HOMU

Poaceae

none

Medium, 

Red Flag 

Moderate 

 Unknown

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

49 
 Hydrilla verticillata 

Synonym: none

hydrilla 

HYVE3

Hydrocharitaceae

Prohibited

Evaluated, 

Not Listed, Red Flag 

High - Alert 

 High

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

50 
 Lepidium latifolium 

Synonym: none

broad leaved 

pepperweed 

LELA2

Brassicaceae

none

High - 

Alert, Red Flag 

High 

 High

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

51 
 Leucanthemum vulgare 

Synonym: none

oxeye daisy 

LEVU

Asteraceae

none

Low 

Moderate 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

52 
 Linaria dalmatica 

Synonym: Linaria genistifolia ssp. 

dalmatica

Dalmatian 

toadflax 

LIDA

Scrophulariaceae

Prohibited, 

Restricted

Medium, 

Red Flag 

not assessed at 

present 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

53 
 Lolium perenne 

Synonym: none

perennial 

ryegrass 

LOPE

Poaceae

none

Medium 

not assessed at 

present 

 Medium

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

54 
 Melilotus officinalis 

Synonym: Melilotus alba, Melilotus 

albus

yellow 

sweetclover 

MEOF

Fabaceae

none

Medium, 

Red Flag 

Evaluated, Not 

Listed 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

55 
 Mesembryanthemum crystallinum

Synonym: none

common iceplant 

MECR3

Aizoaceae

none

Low 

Moderate - 

Alert 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

56 
 Mesembryanthemum nodiflorum 

Synonym: none

slenderleaf 

iceplant 

MENO2

Aizoaceae

none

Medium - 

Alert 

not assessed at 

present 

 Unknown 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

57 
 Myriophyllum aquaticum 

Synonym: none

parrot feather 

watermilfoil 

MYAQ2

Haloragaceae

none

High - 

Alert 

High - Alert 

 High

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

58 
 Onopordum acanthium 

Synonym: none

Scotch 

cottonthistle, Scotch thistle 

ONAC

Asteraceae

Prohibited, 

Restricted

Low 

High 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

59 
 Pennisetum ciliare 

Synonym: Cenchrus ciliaris

buffelgrass 

PECI

Poaceae

Prohibited, 

Regulated

High, Red 

Flag 

not assessed at 

present 

 High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

60 
 Pennisetum setaceum 

Synonym: none

crimson 

fountaingrass, fountaingrass 

PESE3

Poaceae

none

High, Red 

Flag 

Moderate 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

61 
 Phleum pratense 

Synonym: none

timothy 

PHPR3

Poaceae

none

not 

assessed at present 

not assessed at 

present 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

62 
 Potentilla recta 

Synonym: none

sulfur cinquefoil 

PORE5

Rosaceae

none

not 

assessed at present 

not assessed at 

present 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

63 
 Rhus lancea 

Synonym: none

African sumac 

RHLA11

Anacardiaceae

none

Medium - 

Alert 

not assessed at 

present 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

64 
 Rubus armeniacus 

Synonym: Rubus procerus, Rubus 

discolor

Himalayan 

blackberry 

RUAR9

Rosaceae

none

Medium - 

Alert 

High 

 Unknown 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

65 
 Saccharum ravennae 

Synonym: Erianthus ravennae

ravennagrass 

SARA3

Poaceae

none

Medium - 

Alert 

not assessed at 

present 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

66 
 Salsola spp.

Species covered: Salsola collina, 

Salsola tragus

Russian thistle 

SALSO

Chenopodiaceae

none

Medium 

(for Salsola collina, Salsola tragus) 

Limited (for 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

Salsola tragus) 

 not assessed 

at present

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

67 
 Salvinia molesta 

Synonym: none

Kariba-weed, 

giant salvinia 

SAMO5

Salviniaceae

Prohibited, 

Regulated

High - 

Alert 

High - Alert 

 Medium

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

68 
 Schismus spp.

Species covered: Schismus 

arabicus, Schismus barbatus

Mediterranean 

grass 

SCHIS

Poaceae

none

Medium 

Limited 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

69 
 Sonchus asper 

Synonym: none

spiny sowthistle 

SOAS

Asteraceae

none

Medium 

Evaluated, Not 

listed 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

70 
 Sonchus oleraceus 

Synonym: none

common 

sowthistle, annual sowthistle 

SOOL

Asteraceae

none

Medium 

not assessed at 

present 

 not assessed 

at present

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

71 
 Sorghum halepense 

Synonym: none

Johnsongrass 

SOHA

Poaceae

none

Medium 

not assessed at 

present 

 High 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

72 
 Taeniatherum caput-medusae 

Synonym: Elymus caput-medusae

medusahead 

TACA8

Poaceae

none

not 

assessed at present 

High 

 High

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

73 
 Tamarix spp.

Species covered: Tamarix 

chinensis, Tamarix parviflora, 

Tamarix ramosissima

saltcedar 

TAMAR2

Tamaricaceae 

none

High, Red 

Flag (for Tamarix chinensis, 

Tamarix parviflora, Tamarix 

ramosissima) 

High (for 

Tamarix parviflora, Tamarix 

ramosissima) 

 High (for 

Tamarix ramosissima) 

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

74 
 Ulmus pumila 

Synonym: none

Siberian elm 

ULPU

Ulmaceae

none

Medium 

Evaluated, Not 

Listed 

 Medium 

Common Name: 

USDA Plant Code: 

Family: 

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

75 
 Verbascum thapsus 

Synonym: none

common mullein 

VETH

Scrophulariaceae

none

Evaluated, 

Not Listed 

Limited 

 Medium 

Common Name: 

USDA Plant Code: 

Family:

Arizona legal listing: 

AZ-WIPWG category: 

Cal-IPC category: 

NatureServe ranking:

Map legend: 

No records

1-10 records

11-100 records

101-1000 records

>1000 records 

SWEMP occurrence records by County 

SWEMP occurrence records by 

 Weed Management Area SWEMP occurrence records by 

7.5” Topographic Quadrangles 

76 
Other than this note, this page intentionally left blank.
U.S. Geological Survey

Southwest Biological Science Center

2255 N. Gemini Drive

Flagstaff, AZ 86001