Cultural Control of Noxious Weeds
Cultural Control by Category
Cultural Control Links By Category

category 1: Category 1 noxious weeds are weeds that are currently established and generally widespread in many counties of the state.  Management criteria includes awareness and education, containment and suppression of existing infestations and prevention of new infestations.  These weeds are capable of rapid spread and render land unfit or greatly limit beneficial uses.
(a)  Canada thistle (Cirsium arvense)
(b)  field bindweed (Convolvulus arvensis)
(c)  whitetop or hoary cress  (Cardaria draba)
(d)  leafy spurge (Euphorbia esula)   
(e)  Russian knapweed (Centaurea repens)
(f)   spotted knapweed (Centaurea maculosa)   
(g)  diffuse knapweed (Centaurea diffusa)
(h)  common tansy (Tanacetum vulgare L.)
(i)   Dalmatian toadflax (Linaria dalmatica)

(j)   St. Johnswort (Hypericum perforatum)
(k)  sulfur (erect) cinquefoil (Potentilla recta)
(l)   common tansy (Tanacetum vulgare L.)
(m)  ox-eye daisy (Chrysanthemum leucanthemum L.)  
(n)  houndstongue (Cyfnoglossum officinale L.)
(o)  hoary alyssum (Berteroa incana)
(p)  yellow toadflax (Linaria vulgaris)

category 2: Category 2 noxious weeds have recently been introduced into the state or are rapidly spreading from their current infestation sites.  These weeds are capable of rapid spread and invasion of lands, rendering lands unfit for beneficial uses.  Management criteria includes awareness and education, monitoring and containment of known infestations and eradication where possible.
(a)   blueweed (Echium vulgare)
(b)   purple loosestrife or lythrum (Lythrum salicaria, L. virgatum, and any hybrid crosses thereof)
(c)   tansy ragwort (Senecio jacobea L.)
(d)   meadow hawkweed complex (Hieracium pratense, H. floribundum, H. piloselloides)
(e)   orange hawkweed (Hieracium aurantiacum L.)
(f)    tall buttercup (Ranunculus acris L.)
(g)   tamarisk [saltcedar] (Tamarix spp.)
(h)   perennial pepperweed (Lepidium latifolium)
(i)    rush skeletonweed (Chondrilla juncea)
(j)    yellow flag iris (Iris pseudacorus)

category 3: Category 3 noxious weeds have not been detected in the state or may be found in only small, scattered, localized infestations.  Management criteria includes awareness and education, early detection, and immediate action to eradicate infestations.  These weeds are known pests in nearby states and are capable of rapid spread and render land unfit for beneficial uses.
a)   common crupina (Crupina vulgaris)
(b)  dyers woad
(Isatis tinctoria)
(c)  yellow starthistle (Centaurea solstitialis)
(d)   Eurasiam watermilfoil (Myriophyllum spicatum)
(e)   flowering rush (Butomus umbellatus)
(f)   Japanese knotweed (Polygonum spp. [P. cuspidatum, P. sachalinense & P. polystachyum])

category 4: Watch list.  Category 4 plant species are plants that are invasive and may cause significant economic or environmental impacts if allowed to become established in Montana.  Research and monitoring for category 4 plant species may result in future listing as a category 1, 2, or 3 noxious weed in Montana.  Plant species designated as a category 4 plant are prohibited from sale in or into Montana.  AUTH: sec. 80-7-802, MCA.  IMP: sec. 7-22-2101, MCA.
(a)   Scotch broom  (Cytisus scoparius

Reason: The montana Dept. of Agriculture received recommendation from the Noxious Weed List Committee to create a Category 4 designation and to list scotch broom in this category.  The intent of Category 4 listings is to prohibit nursery trade for plants that are invasive and may cause significant economic or environmental impacts if allowed to become established in Montana.


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