Friday, November 24, 2017
Blackfoot Drainage New Weeds Risk Assessment

Species Summaries

The following summary is provided for each species on the alert list:

Scientific name
Family
Common name
Continent of origin

Life form
Duration
Growth habit
Propagation
Dispersal

Weeds of the West page: *page number if described in Whitson et al. (1991)

Western states/provinces listing as noxious (any category): state/province names

Montana Weed Seed Free Forage Program: *

Brooklyn Botanic Garden Invasive Plants list: *whether the species is included in the Encyclopedia of Invasive Plants (Randall and Marinelli 1996)

National EPPC list: *whether listed by on the National Association of Exotic Pest Plant Councils "Worst Invasive Plant Species in the Continental United States" (Sept. 1997 update) - species invasive in wildland ecosystems

Pacific NW EPPC status: *from the Pacific Northwest Exotic Pest Plant Council "Non-native Pest Plants of Greatest Concern in Oregon and Washington as of August 1997."  The focus of this list is on "the impacts that non-native plants currently have or could have upon wildlands, including natural areas; national, state and community parks; wildlife areas; and all other public lands that have not been highly disrupted by human activities."

* NL = not listed, Y = present on the list

Countries reporting as an agricultural weed: from Holm et al. (1979)

Listed as noxious in Australia?: Parsons and Cuthbertson (1992).

Earliest record in the 5 northwest states: Oregon, Washington, Idaho, Montana and Wyoming - year of first record from the INVADERS Database (Rice 1997)

Number of counties with records in the 5 northwest states as of 1996: from INVADERS

Counties with records in the larger Blackfoot infiltration area as of 1996: the 11-county area analyzed includes the Blackfoot River counties Missoula and Powell, plus the adjacent surrounding counties Mineral, Sanders, Lake, Flathead, Lewis and Clark, Jefferson, Deer Lodge, Granite and Ravalli.

Total number of records in the 11-county Blackfoot infiltration area as of 1996: INVADERS

Comments: susceptible cover types or habitat types if known, other miscellaneous comments

(Literature Cited)



Scientific name: Abutilon theophrasti
Family: Malvaceae
Common name: velvetleaf
Continent of origin: Asia

Life form: forb
Duration: annual
Growth habit: erect
Propagation: seeds
Dispersal:

Weeds of the West page: 382
Western states/provinces listing as noxious (any category): British Columbia, Colorado, Manitoba, Oregon, Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Most invasive - regional
Countries reporting as an agricultural weed: Canada, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1885
Number of counties with records in the 5 northwest states as of 1996: 44
Counties with records in the Blackfoot infiltration area as of 1996: Missoula, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: Velvetleaf has been a problem weed primarily on cultivated land, especially in corn and soybeans in the Midwestern U.S.  It was first recorded in Montana in 1956 and has been reported as a weed of gardens and disturbed areas. It is not frost hardy and its weed potential in western Montana may be limited.

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Scientific name: Aegilops cylindrica
Family: Poaceae
Common name: jointed goatgrass
Continent of origin: Eurasia

Life form: grass
Duration: winter annual
Growth habit: erect
Propagation: seeds
Dispersal: seed contaminant, vehicles and machinery

Weeds of the West page: 408
Western states/provinces listing as noxious (any category): Arizona, British Columbia, California, Colorado, Idaho, Oregon, Washington
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: Less invasive
Countries reporting as an agricultural weed: Turkey, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1917
Number of counties with records in the 5 northwest states as of 1996: 21
Counties with records in the larger Blackfoot infiltration area as of 1996: Granite
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 1

Comments: Primarily a weed of wheat fields, but can also spread to roadsides, waste areas, alfalfa fields and grasslands.

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Scientific name: Aegopodium podagraria
Family: Apiaceae
Common name: bishop's goutweed
Continent of origin: Europe

Life form: forb
Duration: perennial
Growth habit:
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Finland, Germany, Soviet Union, Iceland, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1959
Number of counties with records in the 5 northwest states as of 1996: 14
Counties with records in the larger Blackfoot infiltration area as of 1996: Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 1

Comments: Worldwide, this species is occurring more and more as a troublesome weed.  Its weed potential in western Montana is uncertain.

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Scientific name: Anchusa arvensis
Family: Boraginaceae
Common name: small bugloss
Continent of origin: Europe

Life form: forb
Duration: annual
Growth habit: erect or sprawling
Propagation: seed
Dispersal: machinery

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Manitoba, Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: Needs more information
Countries reporting as an agricultural weed: England, Finland, Iceland, Soviet Union
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1916
Number of counties with records in the 5 northwest states as of 1996: 12
Counties with records in the larger Blackfoot infiltration area as of 1996: Mineral, Missoula, Ravalli
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 6

Comments: Weed of cultivated fields, especially in small grains.

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Scientific name: Anchusa officinalis
Family: Boraginaceae
Common name: common bugloss
Continent of origin: Eurasia

Life form: forb
Duration: perennial, biennial
Growth habit: erect
Propagation: seeds
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: Needs more information
Countries reporting as an agricultural weed: Soviet Union, Turkey, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1918
Number of counties with records in the 5 northwest states as of 1996: 20
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake, Mineral
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 5

Comments: Can invade disturbed grassland and dry forest sites.  Needs to be further evaluated for weed potential.

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Scientific name: Atriplex heterosperma
Family: Chenopodiaceae
Common name: weedy orache
Continent of origin: Eurasia

Life form: forb
Duration: annual
Growth habit:
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1953
Number of counties with records in the 5 northwest states as of 1996: 19
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake, Lewis & Clark, Powell
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 7

Comments: Reported from 10 Montana counties since first detected in 1953.  Has occurred as a weed of moist roadsides, disturbed areas and gardens.

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Scientific name: Bryonia alba
Family: Cucurbitaceae
Common name: white bryony
Continent of origin: Eurasia

Life form: forb (herbaceous vine)
Duration: perennial
Growth habit: climbing
Propagation: berry, tubers?
Dispersal: birds

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1953
Number of counties with records in the 5 northwest states as of 1996: 23
Counties with records in the larger Blackfoot infiltration area as of 1996: Missoula
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 8

Comments: Invasive vine of riparian habitats and wooded ravines in grassland, sagebrush and Ponderosa pine zones, and has also occurred on dry grassland sites.

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Scientific name: Butomus umbellatus
Family: Butomaceae
Common name: flowering rush
Continent of origin: Eurasia

Life form: forb
Duration: perennial
Growth habit: erect (emergent aquatic)
Propagation: seeds, rhizomes, vegetative fragments, bulblets
Dispersal: water, escapes cultivation, animals

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Manitoba
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Iran, Iraq, Portugal, Belgium, France, Germany, Turkey
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1956
Number of counties with records in the 5 northwest states as of 1996: 5
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 3

Comments: Aggressively invades wetland habitats, including freshwater marshes and riparian shore areas.

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Scientific name: Carduus acanthoides
Family: Asteraceae
Common name: plumeless thistle
Continent of origin: Europe

Life form: forb
Duration: annual, biennial
Growth habit: erect
Propagation: seeds
Dispersal: wind

Weeds of the West page: 74
Western states/provinces listing as noxious (any category): California, Arizona, Colorado, Manitoba, Nebraska, Washington, Wyoming
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Most invasive - regional
Countries reporting as an agricultural weed: Argentina, Canada, England, Soviet Union, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1911
Number of counties with records in the 5 northwest states as of 1996: 11
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Ravalli
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 3

Comments: First recorded in Montana in 1977 (Flathead Co.) and continuing to spread.  Invades disturbed grassland and forest sites, pastures, hay fields, roadsides, and stream bottoms in the grassland and dry forest zones.
 
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Scientific name: Chaenorrhinum minus
Family: Scrophulariaceae
Common name: dwarf snapdragon
Continent of origin: Europe

Life form: forb
Duration: annual
Growth habit: erect
Propagation: seeds
Dispersal: wind, vehicles and machinery

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: Needs more information
Countries reporting as an agricultural weed: United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1976
Number of counties with records in the 5 northwest states as of 1996: 9
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Missoula
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 4

Comments: Has recently been spreading rapidly along railroads and roadsides.  Weed potential in western Montana is uncertain.

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Scientific name: Coronilla varia
Family: Fabaceae
Common name: trailing crownvetch
Continent of origin: Europe

Life form: forb
Duration: perennial
Growth habit: climbing / trailing
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: Y
National EPPC list: Y
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Iran, Soviet Union, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1951
Number of counties with records in the 5 northwest states as of 1996: 12
Counties with records in the larger Blackfoot infiltration area as of 1996: Ravalli, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: Aggressive invader of open, upland areas in the Northeast and Midwestern U.S.

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Scientific name: Diplotaxis muralis
Family: Brassicaceae
Common name: sand rocket
Continent of origin: Europe

Life form: forb
Duration: annual, biennial, perennial
Growth habit:
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Spain, Argentina, Iran, South Africa, Chile, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1899
Number of counties with records in the 5 northwest states as of 1996: 5
Counties with records in the larger Blackfoot infiltration area as of 1996: Lewis & Clark
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 3

Comments: Although recorded at Portland, OR in the late 1800s, sand rocket was not known in Montana until 1977.  It has since been reported from 4 Montana counties.  Weed potential is uncertain.

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Scientific name: Echium vulgare
Family: Boraginaceae
Common name: blueweed
Continent of origin: Europe

Life form: forb
Duration: biennial, perennial
Growth habit: erect
Propagation: seeds
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Alberta, Manitoba, Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: Most invasive - regional
Countries reporting as an agricultural weed: Australia, Canada, South Africa, Soviet Union, Spain, Chile, New Zealand, Turkey, United States
Listed as noxious in Australia?: Y

Earliest record in the 5 northwest states: 1925
Number of counties with records in the 5 northwest states as of 1996: 23
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake, Mineral, Missoula, Ravalli, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 15

Comments: May be episodic in it appearance in western Montana grasslands, where it is most successful in somewhat disturbed mesosites similar to woolly mullein (Verbascum thapsus).

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Scientific name: Elaeagnus angustifolia
Family: Elaeagnaceae
Common name: Russian olive
Continent of origin: Eurasia

Life form: tree
Duration: perennial
Growth habit: erect
Propagation: seeds
Dispersal: escapes cultivation

Weeds of the West page: 304
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: Y
National EPPC list: Y
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1923
Number of counties with records in the 5 northwest states as of 1996: 38
Counties with records in the larger Blackfoot infiltration area as of 1996: Lake
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 1

Comments: Drought tolerant. Invades stream banks, lake shores and wet meadows, choking out native vegetation such as cottonwoods and willows. It has been planted for windbreaks and as food and protection for wildlife, however many wildlife managers in Canada and the northern US are now suggesting that this small tree is a more significant management problem than tamarisk species.

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Scientific name: Gypsophila paniculata
Family: Caryophyllaceae
Common name: babysbreath
Continent of origin: Asia

Life form: forb
Duration: perennial
Growth habit: erect
Propagation:
Dispersal:

Weeds of the West page: 252
Western states/provinces listing as noxious (any category): California, Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: Y
National EPPC list: Y
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1929
Number of counties with records in the 5 northwest states as of 1996: 30
Counties with records in the larger Blackfoot infiltration area as of 1996: Deer Lodge, Flathead, Jefferson, Lake, Lewis & Clark, Missoula, Ravalli
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 19

Comments: Grown in the northwest, including Montana, for sale in cut flower shops, it escapes cultivation, and forms dense stands that are difficult to control. Widely and increasingly reported as an invasive species.  The commercial trade value presents obstacles for wildlands management.

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Scientific name: Hieracium aurantiacum
Family: Asteraceae
Common name: orange hawkweed
Continent of origin: Europe

Life form: forb
Duration: perennial
Growth habit: erect
Propagation: seeds, stolons
Dispersal: animals, escapes from cultivation

Weeds of the West page: 142
Western states/provinces listing as noxious (any category): Idaho, Manitoba, Washington, likely to be listed by the State of Montana in 1998
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Most invasive - regional
Countries reporting as an agricultural weed: Canada, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1927
Number of counties with records in the 5 northwest states as of 1996: 36
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake, Lewis & Clark, Mineral, Missoula, Ravalli, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 48

Comments: Invades mountain meadows, clearings in forest zones, pastures and hayfields, cleared timber units and abandoned farmland.  Susceptible habitat types include the more mesic Ponderosa pine types  (e.g., ponderosa pine/snowberry, ponderosa pine/ninebark), most Douglas fir types (e.g., Douglas fir/ninebark, Douglas fir/blue huckleberry, Douglas fir/snowberry, Douglas fir/pinegrass, Douglas fir/elk sedge), and most of the spruce, grand fir, western redcedar, western hemlock, subalpine fir and lodgepole pine series.

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Scientific name: Hieracium floribundum
Family: Asteraceae
Common name: yellow-devil hawkweed
Continent of origin: Europe

Life form: forb
Duration: perennial
Growth habit: erect
Propagation: seeds, stolons
Dispersal: animals

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Manitoba, likely to be listed by the State of Montana in 1998
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1989
Number of counties with records in the 5 northwest states as of 1996: 4
Counties with records in the larger Blackfoot infiltration area as of 1996: Lake
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 3

Comments: Meadow (H. pratense), yellow-devil (H. floribundum), and kingdevil (H. piloselloides) hawkweeds are morphologically, if not ecologically, quite similar. There is reason to believe that these three species are crossbreeding in the northwest. These three yellow flowered hawkweeds should be managed as a complex at this time. See additional comments under meadow hawkweed (H. pratense).
 
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Scientific name: Hieracium piloselloides
Family: Asteraceae
Common name: kingdevil hawkweed
Continent of origin: Eurasia

Life form: forbs
Duration: perennial
Growth habit: erect
Propagation: seeds
Dispersal: animals

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Manitoba, likely to be listed by the State of Montana in 1998
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1988
Number of counties with records in the 5 northwest states as of 1996: 2
Counties with records in the larger Blackfoot infiltration area as of 1996: Lake
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: Meadow (H. pratense), yellow-devil (H. floribundum), and kingdevil (H. piloselloides) hawkweeds are morphologically, if not ecologically, quite similar. There is reason to believe that these three species are crossbreeding in the northwest. These three yellow flowered hawkweeds should be managed as a complex at this time. See additional comments under meadow hawkweed (H. pratense).

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Scientific name: Hieracium pratense
Family: Asteraceae
Common name: meadow hawkweed
Continent of origin: Europe

Life form: forb
Duration: perennial
Growth habit: erect
Propagation: seeds, stolons, root fragments
Dispersal: animals

Weeds of the West page: 143
Western states/provinces listing as noxious (any category): Idaho, Washington, likely to be listed by the State of Montana in 1998
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: N
National EPPC list: N
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1969
Number of counties with records in the 5 northwest states as of 1996: 24
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake, Mineral, Missoula, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 23

Comments: Invades mountain meadows, clearings in forest zones, pastures and hayfields, cleared timber units and abandoned farmland.  Susceptible habitat types are similar to those for orange hawkweed (Hieracium aurantiacum), except that meadow hawkweed may not extend as far into the colder subalpine habitat types.
Meadow (H. pratense), yellow-devil (H. floribundum), and kingdevil (H. piloselloides) hawkweeds are morphologically, if not ecologically, quite similar. There is reason to believe that these three species are crossbreeding in the northwest. These three yellow flowered hawkweeds should be managed as a complex at this time.

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Scientific name: Iris pseudacorus
Family: Iridaceae
Common name: yellowflag iris
Continent of origin: Europe, Africa

Life form: forb
Duration: perennial
Growth habit: erect
Propagation: rhizomes, vegetative fragments, seeds
Dispersal: water

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Nevada
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Most invasive - regional
Countries reporting as an agricultural weed: Argentina, Iran, Portugal, Spain, Belgium, England, France, Germany, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1948
Number of counties with records in the 5 northwest states as of 1996: 12
Counties with records in the larger Blackfoot infiltration area as of 1996: Lake, Missoula
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 3

Comments: Can form dense stands in wetland habitats.  Problematic in the Ninepipe Wildlife Management Area.

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Scientific name: Knautia arvensis
Family: Dipsacaceae
Common name: bluebuttons
Continent of origin: Eurasia, Africa

Life form: forb
Duration: perennial
Growth habit: erect
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Finland, Poland, Spain, Puerto Rico, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1932
Number of counties with records in the 5 northwest states as of 1996: 23
Counties with records in the larger Blackfoot infiltration area as of 1996: Lewis & Clark, Powell, Ravalli
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 13

Comments: Has spread throughout southwestern and central Montana in recent decades, occurring in hay meadows, cultivated fields, roadsides and ditch banks.

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Scientific name: Lepidium latifolium
Family: Brassicaceae
Common name: perennial pepperweed
Continent of origin: Eurasia

Life form: forb
Duration: perennial
Growth habit: erect
Propagation: seeds, roots
Dispersal: machinery, seed contaminant

Weeds of the West page: 230
Western states/provinces listing as noxious (any category): California, Colorado, Idaho, Oregon, Nevada, New Mexico, Utah, Washington
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: Lebanon, Turkey, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1932
Number of counties with records in the 5 northwest states as of 1996: 37
Counties with records in the larger Blackfoot infiltration area as of 1996: Lake, Lewis & Clark, Powell
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 12

Comments: Wide ecological amplitude.  Spreads along riparian corridors and into hay meadows, cultivated fields, and possibly grasslands and disturbed forest sites.  Difficult to control.

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Scientific name: Malcolmia africana
Family: Brassicaceae
Common name: malcolm stock
Continent of origin: Europe

Life form: forb
Duration: annual
Growth habit:
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Iran, Pakistan
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1931
Number of counties with records in the 5 northwest states as of 1996: 12
Counties with records in the larger Blackfoot infiltration area as of 1996: Lewis & Clark
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: Arid-region weed of disturbed rangeland and roadsides.  Spreading northward from the Great Basin area and first recorded in Montana in 1976.
 
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Scientific name: Matricaria maritima
Family: Asteraceae
Common name: scentless chamomile
Continent of origin: Europe

Life form: forb
Duration: annual, biennial and perennial forms
Growth habit: prostrate
Propagation: seed
Dispersal: equipment and vehicles, seed/feed contaminant, water

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Alberta, British Columbia, Saskatchewan, Washington
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: NL
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Canada, Germany, Iceland, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1902
Number of counties with records in the 5 northwest states as of 1996: 45
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Granite, Lake, Lewis & Clark, Missoula, Ravalli, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 37

Comments: Troublesome agricultural weed in Canada. First recorded in Montana in 1952. Has been spreading along riparian corridors in western and central Montana. Spread into adjacent grass and hay fields has been limited so far.
 
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Scientific name: Onopordum acanthium
Family: Asteraceae
Common name: Scotch thistle
Continent of origin: Eurasia

Life form: forb
Duration: biennial, annual
Growth habit: erect
Propagation: seeds, root fragments
Dispersal: wind, animals, machinery, seed contaminant

Weeds of the West page: 164
Western states/provinces listing as noxious (any category): Arizona, California, Colorado, Idaho, Manitoba, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Most invasive - regional
Countries reporting as an agricultural weed: Australia, Argentina, England, Soviet Union, Spain, New Zealand, Turkey, United States
Listed as noxious in Australia?: Y

Earliest record in the 5 northwest states: 1945
Number of counties with records in the 5 northwest states as of 1996: 81
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: Has potential to invade pastures, grasslands, stream bottoms,  and disturbed forest sites especially in the ponderosa pine and Douglas fir zones.

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Scientific name: Polygonum cuspidatum
Family: Polygonaceae
Common name: Japanese knotweed
Continent of origin: Asia

Life form: forb
Duration: perennial
Growth habit: erect/creeping
Propagation: rhizomes, vegetative fragments, seeds(?)
Dispersal: water, transported soil

Weeds of the West page: 506
Western states/provinces listing as noxious (any category): California, Manitoba, Oregon, Washington
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: N
National EPPC list: Y
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: China, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1957
Number of counties with records in the 5 northwest states as of 1996: 52
Counties with records in the larger Blackfoot infiltration area as of 1996: Missoula, Ravalli, Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 6

Comments: This rhizomatous perennial is an aggressive weed in the British Isles and central and northern Europe where it often forms dense stands along water courses, replacing the native riparian vegetation.  It has been spreading rapidly in the northwest United States, facilitated by planting as an ornamental.

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Scientific name: Polygonum polystachyum
Family: Polygonaceae
Common name:
Continent of origin: Asia

Life form: shrub
Duration: perennial
Growth habit: erect
Propagation:
Dispersal:

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): California
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: N
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1934
Number of counties with records in the 5 northwest states as of 1996: 11
Counties with records in the larger Blackfoot infiltration area as of 1996: Sanders
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 1

Comments:

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Scientific name: Polygonum sachalinense
Family: Polygonaceae
Common name: sakhalin knotweed
Continent of origin: Asia

Life form: forb
Duration: perennial
Growth habit: erect
Propagation: rhizomes, vegetative fragments, seeds(?)
Dispersal: water, transported soil

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): California
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: Japan, New Zealand, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1918
Number of counties with records in the 5 northwest states as of 1996: 29
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lake, Lewis & Clark, Missoula, Sanders, Ravalli
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 12

Comments: Similar to Japanese knotweed in appearance and ecology.

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Scientific name: Rhamnus cathartica
Family: Rhamnaceae
Common name: European buckthorn
Continent of origin: Eurasia

Life form: shrub
Duration: perennial
Growth habit: erect
Propagation: seeds
Dispersal: birds, escapes cultivation

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): Manitoba
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: Y
National EPPC list: Y
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: Canada, United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1921
Number of counties with records in the 5 northwest states as of 1996: 26
Counties with records in the larger Blackfoot infiltration area as of 1996: Flathead, Lewis & Clark, Missoula, Ravalli
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 11

Comments: Major problem plant in the northeastern and north central third of the U.S., where it has invaded woodlands, savannahs, prairies, abandoned agricultural fields and roadsides.  It can form dense thickets that displace native species.  All parts of the plant contain anthraquinones, which cause vomiting and diarrhea if eaten.  It is an alternate host for the fungus that causes oat rust.

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Scientific name: Scorzonera laciniata
Family: Asteraceae
Common name: self salsify
Continent of origin: Europe

Life form: forb
Duration: annual
Growth habit: erect
Propagation: seeds
Dispersal: vehicles, wind (limited)

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): none
Montana Weed Seed Free Forage Program: NL
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: N
Pacific NW EPPC status: NL
Countries reporting as an agricultural weed: none
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1980
Number of counties with records in the 5 northwest states as of 1996: 8
Counties with records in the larger Blackfoot infiltration area as of 1996: Sanders, Powell
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: A recent invader that has spread very rapidly throughout much of the western United States since first detected along the foothills of the Front Range near Boulder, CO in the mid-50s.  Weed potential in western Montana is uncertain.
 
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Scientific name: Tribulus terrestris
Family: Zygophyllaceae
Common name: puncturevine
Continent of origin: Eurasia, Africa

Life form: forb
Duration: annual, perennial
Growth habit: prostrate
Propagation: seeds
Dispersal: animals, vehicles, wool contaminant

Weeds of the West page: 600
Western states/provinces listing as noxious (any category): California, Colorado, Nevada, Oregon, Washington
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Less invasive
Countries reporting as an agricultural weed: Australia, Cambodia, Greece, Hawaii, India, Iran, Israel, Kenya, Lebanon, Madagascar (Malagasy), Mozambique, Pakistan, South Africa, Switzerland, Turkey, Argentina, Ethiopia, Iraq, Morocco, Portugal, Rhodesia (Zimbabwe), Spain, Tanzania, United States, Arabian Peninsula, China, France, Ghana, Italy, Jordan, Japan, Mauritius, Soviet Union, Sudan, Thailand, Trinidad, Vietnam, Yugoslavia, Zambia
Listed as noxious in Australia?: Y

Earliest record in the 5 northwest states: 1922
Number of counties with records in the 5 northwest states as of 1996: 38
Counties with records in the larger Blackfoot infiltration area as of 1996: Missoula
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 2

Comments: Spines on the fruit damage the feet of animals, particularly horses, sheep, cattle and dogs, and are a nuisance to humans.  The fruits can become entangled in wool causing problems for shearers, and when eaten by animals can injure the mouth and possibly damage the lining of the stomach and intestines.  Also toxic to animals, mainly sheep.

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Scientific name: Zygophyllum fabago
Family: Zygophyllaceae
Common name: Syrian beancaper
Continent of origin: Eurasia

Life form: forb
Duration: perennial
Growth habit: erect to spreading
Propagation: seeds, lateral roots, regeneration from root fragments
Dispersal: machinery, transported soil

Weeds of the West page: NL
Western states/provinces listing as noxious (any category): California, Idaho, Washington
Montana Weed Seed Free Forage Program: Y
Brooklyn Botanic Garden Invasive Plants list: NL
National EPPC list: Y
Pacific NW EPPC status: Red alert - high potential to spread
Countries reporting as an agricultural weed: United States
Listed as noxious in Australia?: N

Earliest record in the 5 northwest states: 1927
Number of counties with records in the 5 northwest states as of 1996: 8
Counties with records in the larger Blackfoot infiltration area as of 1996: Lewis & Clark, Powell
Total number of records in the 11-county Blackfoot infiltration area as of 1996: 3

Comments: Limited spread has been reported in Montana since first detected in mid-1950s.  Needs further study to define susceptible habitats and potential impacts.


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