Weeds of Oklahoma

Common Name	Latin Name	Competitiveness Rating	Comments and Conditions
alfalfa dodder	Cuscuta suaveolens Ser.	Low	Not usually a problem with haying, but need to control if harvesting alfalfa seed.
amaranth, Palmer	Amaranthus palmeri S. Wats.	High	Major summer weed problem in new spring plantings and thinning stands.
annual bluegrass	Poa annua L.	Low	Occasionally in thin stands.
Asiatic dayflower	Commelina communis L.	Medium	Sometimes present, but seldom a problem
barley, little	Hordeum pusillum Nutt.	Low	Sometimes coming into thinning stands. Low quality, so need to control.
barnyardgrass	Echinochloa crus-galli (L.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
bearded sprangletop	Leptochloa fascicularis (Lam.) Gray	High	Can be a problem in newly spring-planted and in thinning stands.
bermudagrass	Cynodon dactylon (L.) Pers.	High	Can be a major problem if established plants not controlled before planting alfalfa.
blue mustard	Chorispora tenella (Pallas) DC.	High	Currently only present in northern most counties of northwest Oklahoma. Can become a major problem in fall establishment of new stands.
bluegrass, annual	Poa annua L.	Low	Occasionally in thin stands.
brome, downy	Bromus tectorum L.	High	Primary winter grass coming into thinning stands. Poor forage quality, so need to control.
brome, Japanese	Bromus japonicus Thunb. ex Murr.	High	Can be a problem in newly fall-planted and in thinning stands.
buckhorn plantain (also English plantain, ribwort, ribgrass, narrowleaf plantain)	Plantago lanceolata L.	Low	Some problem in NE Oklahoma in seedling and established stands.
buffalobur	Solanum rostratum Dun.	Medium	Occasionally a problem in spring-planted stands on newly plowed areas.
bull thistle	Cirsium vulgare	NA	Not normally found in alfalfa fields.
burning bush (see kochia)
bushy wallflower (also spreading wormseed)	Erysimum repandum L.	Medium	Sometimes in fall-planted stands in northwest Oklahoma.
Canada thistle	Cirsium discolor	NA	Not normally found in alfalfa fields.
cheat	Bromus secalinus L.	High	Major problem in fall-planted alfalfa following wheat.
chickweed, common	Stellaria media (L.) Vill.	Low	Often present, but not usually a problem.
common chickweed	Stellaria media (L.) Vill.	Low	Often present, but not usually a problem.
common lambsquarters	Chenopodium album L.	High	Can be a problem in newly spring-planted and in thinning stands.
common ragweed	Ambrosia artemisiifolia L.	High	Can be a problem in newly spring-planted and in thinning stands.
coreopsis, plains	Coreopsis tinctoria Nutt.	Medium	Can be a problem in newly fall-planted and in thinning stands.
crabgrass, large	Digitaria sanguinalis (L.) Scop.	High	Major weed in spring-planted alfalfa and in thinning stands.
crabgrass, smooth	Digitaria ischaemum (Schreb. ex Schweig.) Schreb.	High	Can be a problem in newly spring-planted and in thinning stands.
cupgrass, prairie	Eriochloa contracta Hitchc.	High	Can be a problem in newly spring-planted and in thinning stands.
cupgrass, southwestern	Eriochloa gracilis (Fourn.)A.S.Hitchc.	High	Can be a problem in newly spring-planted and in thinning stands.
curly dock	Rumex crispus L.	Medium	Becomes established at time of planting alfalfa and is usually persistent in low wet areas of field.
cutleaf eveningprimrose,	Oenothera laciniata Hill	Medium	Fairly common in new fall-planted alfalfa.
dayflower, Asiatic	Commelina communis L.	Medium	Sometimes present, but seldom a problem
dandelion	Taraxacum officinale Weber in Wiggers	Low	Sometimes present, but very seldom a problem.
dock, curly	Rumex crispus L.	Medium	Becomes established at time of planting alfalfa and is usually persistent in low wet areas of field.
dodder, alfalfa	Cuscuta suaveolens Ser.	Low	Not usually a problem with haying, but need to control if harvesting alfalfa seed.
downy brome	Bromus tectorum L.	High	Primary winter grass coming into thinning stands. Poor forage quality, so need to control.
English plantain (see buckhorn plantain)
eveningprimrose, cutleaf	Oenothera laciniata Hill	Medium	Fairly common in new fall-planted alfalfa.
field sandbur	Cenchrus incertus M.A.Curtis	High	Major weed problem in sandy areas.
fireweed (see kochia)
flixweed	Descurainia sophia (L.) Webb. ex Prantl	High	Can be a problem in newly fall-planted and in thinning stands. Fairly common mustard in NW Oklahoma.
foxtail, giant	Setaria faberi Herrm.	High	Can be a problem in newly spring-planted and in thinning stands. Distribution limited to NE Oklahoma.
foxtail, green	Setaria viridis (L.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
foxtail, yellow	Setaria glauca (L.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
garlic, wild	Allium vineale L.	Low	Sometimes present, but seldom a problem
giant foxtail	Setaria faberi Herrm.	High	Can be a problem in newly spring-planted and in thinning stands. Distribution limited to NE Oklahoma.
goatgrass, jointed	Aegilops cylindrica Host	High	Can be a problem in newly fall-planted and in thinning stands. Mostly in western Oklahoma.
goosegrass	Eleusine indica (L.) Gaertn.	Medium	Occasionally a problem in low areas in wet years.
greenflower pepperweed	Lepidium densiflorum Schrad.	Medium	Can be a problem in fall-planted and in thinning stands.
green foxtail	Setaria viridis (L.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
henbit	Lamium amplexicaule L.	Low	Usually present, but seldom a problem.
horseweed	Conyza canadensis (L.) Cronq.	Medium	Occasionally a problem in thinning stands.
Italian ryegrass	Lolium multiflorum Lam.	High	Major winter weed problem in newly planted fall stands. Also often in thinning stands. Has good forage quality, so can be utilized as hay or grazing.
Japanese brome	Bromus japonicus Thunb. ex Murr.	High	Can be a problem in newly fall-planted and in thinning stands.
johnsongrass	Sorghum halepense (L.) Pers.	High	Can be a major problem if established plants not controlled before planting alfalfa.
jointed goatgrass	Aegilops cylindrica Host	High	Can be a problem in newly fall-planted and in thinning stands. Mostly in western Oklahoma.
kochia (also fireweed, burning bush)	Kochia scoparia (L.) Schrad.	High	Can be a problem in newly spring-planted and in thinning stands. Mostly in western Oklahoma.
lambsquarters, common	Chenopodium album L.	High	Can be a problem in newly spring-planted and in thinning stands.
lambsquarters, slimleaf	Chenopodium leptophyllum L.	Medium	Can be a problem in newly spring-planted and in thinning stands.
large crabgrass	Digitaria sanguinalis (L.) Scop.	High	Major weed in spring-planted alfalfa and in thinning stands.
lettuce, prickly	Lactuca serriola L.	Medium	Occurs both in newly fall-planted and thinning stands. Large plants hard to dry in hay.
little barley	Hordeum pusillum Nutt.	Low	Sometimes coming into thinning stands. Low quality, so need to control.
musk thistle (also nodding thistle)	Carduus nutans L.	High	Can be a problem in newly fall-planted and in thinning stands.
mustard, blue	Chorispora tenella (Pallas) DC.	High	Currently only present in northern most counties of northwest Oklahoma. Can become a major problem in fall establishment of new stands.
narrowleaf plantain (see buckhorn plantain)
nodding thistle (see musk thistle)
nutsedge, yellow	Cyperus esculentus L.	Medium	Usually not a problem in alfalfa because of frequent cutting of hay.
Palmer amaranth	Amaranthus palmeri S.Wats.	High	Major summer weed problem in new spring plantings and thinning stands.
pepperweed, greenflower	Lepidium densiflorum Schrad.	Medium	Can be a problem in fall-planted and in thinning stands.
pepperweed, veiny	Lepidium oblongum Small	Medium	Can be a problem in fall-planted and in thinning stands of alfalfa. Resistant to the sulfonyurea herbicides
pigweed, redroot	Amaranthus retroflexus L.	High	Can be a problem in newly spring-planted and in thinning stands.
pigweed, tumble	Amaranthus albus L.	Medium	Can be a problem in newly spring-planted and in thinning stands.
pinnate tansymustard	Descurainia pinnata (Walt.) Britt	High	Can be a problem in newly fall-planted and in thinning stands.
plains coreopsis	Coreopsis tinctoria Nutt.	Medium	Can be a problem in newly fall-planted and in thinning stands.
plantain, buckhorn	Plantago lanceolata L.	Low	Some problem in NE Oklahoma in seedling and established stands.
poppy, red horned	Glausium corniculatum (L.) Rudolph	Medium	Becoming a major weed problem in certain western areas in newly fall-planted stands.
prairie cupgrass	Eriochloa contracta Hitchc.	High	Can be a problem in newly spring-planted and in thinning stands.
prickly lettuce	Lactuca serriola L.	Medium	Occurs both in newly fall-planted and thinning stands. Large plants hard to dry in hay.
prickly sowthistle (see spiny sowthistle)
ragweed, common	Ambrosia artemisiifolia L.	High	Can be a problem in newly spring-planted and in thinning stands.
red horned poppy	Glausium corniculatum (L.) Rudolph	Medium	Becoming a major weed problem in certain western areas in newly fall-planted stands.
redroot pigweed	Amaranthus retroflexus L.	High	Can be a problem in newly spring-planted and in thinning stands.
red sprangletop	Leptochloa filiformis (Lam.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
rescuegrass	Bromus catharticus Vahl	High	Major winter weed problem in newly planted fall stands. Also often in thinning stands. Has good forage quality, so can be utilized as hay or grazing.
ribgrass (see buckhorn plantain)
ribwort (see buckhorn plantain)
rush, slender	Juncus tenuis Willd	Low	Occasionally present, but seldom a problem.
Russian thistle	Salsola iberica Sennen & Pau	High	Can be a problem in newly spring-planted and in thinning stands
ryegrass, Italian	Lolium multiflorum Lam.	High	Major winter weed problem in newly planted fall stands. Also often in thinning stands. Has good forage quality, so can be utilized as hay or grazing.
sandbur, field	Cenchrus incertus M.A.Curtis	High	Major weed problem in sandy areas.
scotch thistle	Onopordum acanthium	NA	Not normally found in alfalfa fields.
shepherdspurse	Capsella bursa-pastoris (L.) Medicus	Medium	Commonly found mustard in newly fall-planted alfalfa and in thinning stands.
slender rush	Juncus tenuis Willd	Low	Occasionally present, but seldom a problem.
slimleaf lambsquarters	Chenopodium leptophyllum L.	Medium	Can be a problem in newly spring-planted and in thinning stands.
smooth crabgrass	Digitaria ischaemum (Schreb. ex Schweig.) Schreb.	High	Can be a problem in newly spring-planted and in thinning stands.
southwestern cupgrass	Eriochloa gracilis (Fourn.)A.S.Hitchc.	High	Can be a problem in newly spring-planted and in thinning stands.
sowthistle, spiny (also prickly sowthistle)	Sonchus asper (L.) Hill	Medium	Occasionally found in newly fall-planted and thinning stands.
spiny sowthistle (also prickly sowthistle)	Sonchus asper (L.) Hill	Medium	Occasionally found in newly fall-planted and thinning stands.
sprangletop, bearded	Leptochloa fascicularis (Lam.) Gray	High	Can be a problem in newly spring-planted and in thinning stands.
sprangletop, red	Leptochloa filiformis (Lam.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
spreading wormseed (see bushy wallflower)
tall waterhemp	Amaranthus tuberculatus (Moq.) J.D.Sauer	High	Can be a problem in newly spring-planted and in thinning stands.
tansymustard, pinnate	Descurainia pinnata (Walt.) Britt	High	Can be a problem in newly fall-planted and in thinning stands.
thistle, bull	Cirsium vulgare	NA	Not normally found in alfalfa fields.
thistle, Canada	Cirsium discolor	NA	Not normally found in alfalfa fields.
thistle, musk (also nodding thistle)	Carduus nutans L.	High	Can be a problem in newly fall-planted and in thinning stands.
thistle, Russian	Salsola iberica Sennen & Pau	High	Can be a problem in newly spring-planted and in thinning stands
thistle, scotch	Onopordum acanthium	NA	Not normally found in alfalfa fields.
thistle, wavyleaf	Cirsium undulatum	NA	Not normally found in alfalfa fields.
tumble pigweed	Amaranthus albus L.	Medium	Can be a problem in newly spring-planted and in thinning stands.
veiny pepperweed	Lepidium oblongum Small	Medium	Can be a problem in fall-planted and in thinning stands of alfalfa. Resistant to the sulfonyurea herbicides
volunteer wheat	Triticum aestivum L.	High	Major problem in newly fall-planted stands following wheat.
wallflower, bushy	Erysimum repandum L.	Medium	Sometimes in fall-planted stands in northwest Oklahoma.
waterhemp, tall	Amaranthus tuberculatus (Moq.) J.D.Sauer	High	Can be a problem in newly spring-planted and in thinning stands.
wavyleaf thistle	Cirsium undulatum	NA	Not normally found in alfalfa fields.
wheat, volunteer	Triticum aestivum L.	High	Major problem in newly fall-planted stands following wheat.
wild garlic	Allium vineale L.	Low	Sometimes present, but seldom a problem
windmillgrass	Chloris verticillata Nutt.	Medium	Commonly coming into thinning stands
yellow foxtail	Setaria glauca (L.) Beauv.	High	Can be a problem in newly spring-planted and in thinning stands.
yellow nutsedge	Cyperus esculentus L.	Medium	Usually not a problem in alfalfa because of frequent cutting of hay.