1. Most Common and Troublesome Weeds in
2015 Baseline Results for the U.S. & Canada
(690 survey responses)
Most Common and Troublesome Weeds in
26 Crop, Non-crop, and Aquatic areas
1) alfalfa, 2) aquatic – irrigation & flood control, 3) aquatic – lakes, rivers, reservoirs, 4) aquatic – ponds, 5) canola, 6) corn, 7) cotton, 8) forestry, 9) fruits & nuts, 10) natural areas – parks, wildlife refuges, 11) ornamentals, 12) pastures – rangeland, other hay, 13) peanut, 14) pulse crops, 15) rice, 16) right-of-ways – rail, road, utility, 17) sorghum, 18) soybean, 19) spring cereal grains, 20) sugarbeet, 21) turf, 22) vegetables – cole crops, 23) vegetables – cucurbits, 24) vegetables – fruiting, 25) vegetables – other, and 26) winter cereal grains.
Common weeds refer to those weeds you most frequently see.
Troublesome weeds are those that are most difficult to control, but may not be widespread.
WSSA’s Composite List of Weeds is used for weed common and latin names
Suggested citation: Van Wychen L (2015) 2015 Baseline Survey of the Most Common and Troublesome Weeds in the United States and Canada. Weed Science Society of America National Weed Survey Dataset. Available:

2. Top 5 Weeds in Alfalfa MOST COMMON MOST TROUBLESOME
(16 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
mustard spp. (13)* 2
Bromus spp. (8) 3
dandelion (6)
foxtail spp. (6) 5
common chickweed (5)
Lamium spp. (5) 1
mustard spp. (11)* 2
dandelion (8) 3
Bromus spp. (7) 4
Palmer amaranth (5) 5
Canada thistle (5)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- mustard spp. included flixweed, shepherd’s-purse, field pennycress, wild, tumble, and African mustard, tansymustard spp., London rocket, and wild radish.
- Bromus spp. included downy brome (cheatgrass), cheat and rescuegrass.
- foxtail spp. included giant, green and yellow foxtail.
Lamium spp. included henbit and purple deadnettle.

3. Top 5 Weeds in Aquatic-Irrigation, Flood Control
(7 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
hydrilla (3)*
waterlettuce (3)
sago pondweed (3)
horned pondweed (3) 5
Tie among 5 species (2) 1
hydrilla (3)*
waterlettuce (3) 3
sago pondweed (2)
horned pondweed (2)
alligatorweed (2)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this aquatic area.

4. Top 7 Weeds in Aquatic-Lakes, Rivers, Reservoirs
(58 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Myriophyllum spp.(36)* 2
Potamogeton spp. (30) 3
hydrilla (18) 4
coontail (12)
waterhyacinth (12) 6
Najas spp. (11) 7
Ludwigia spp. (10) 1
Myriophyllum spp.(41)* 2
hydrilla (36) 3
Potamogeton spp. (20) 4
waterhyacinth (17) 5
Salvinia spp. (13) 6
Ludwigia spp. (9)
waterlettuce (9)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this aquatic area.
Myriophyllum spp. included Eurasian, variable and northern watermilfoil, watermilfoil hybrids, and parrotfeather.
Potamogeton spp. included curlyleaf, Illinois, leafy, American and Richardson’s pondweed.
Salvinia spp. included giant salvinia and water fern.
Najas spp. included southern, brittleleaf, and slender naiad.

5. Top 6 Weeds in Aquatic- Ponds
(19 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Potamogeton spp. (11)* 2
common duckweed (10) 3
algae spp. (8) 4
Eurasian watermilfoil (7) 5
Najas spp. (6)
Wolffia spp. (6) 1
common duckweed (8)* 2
algae spp. (7)
Wolffia spp. (7) 4
Eleocharis spp. (6)
hydrilla (6)
Potamogeton spp. (6)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this aquatic area.
Potamogeton spp. included curlyleaf, Illinois, leafy and floatingleaf pondweed.
algae spp. included filamentous and planktonic algae and “harmful algal blooms”.
Eleocharis spp. included slender spikerush.
Najas spp. included southern and hollyleaf naiad.

6. Top 5 Weeds in Canola MOST COMMON MOST TROUBLESOME
(16 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
wild oat (10)* 2
mustard spp. (9) 3
wild buckwheat (8) 4
common lambsquarters (6)
Canada thistle (6)
foxtail spp. (6) 1
wild buckwheat (9)* 2
mustard spp. (8)
Galium spp. (8) 4
wild oat (7) 5
kochia (6)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- mustard spp. included wild, blue, and white mustard, flixweed, tansymustard spp., wild radish and shepherd’s-purse.
- Galium spp. included catchweed bedstraw (cleavers) and false cleavers.
- foxtail spp. included green foxtail.

7. Top 7 Weeds in Corn MOST COMMON MOST TROUBLESOME
(82 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
foxtail spp. (55)* 2
common lambsquarters (43) 3
waterhemp (29) 4
pigweed spp. (28) 5
morningglory spp. (26) 6
velvetleaf (24)
common ragweed (24) 1
waterhemp (38)* 2
Palmer amaranth (33) 3
morningglory spp. (31) 4
giant ragweed (28) 5
common lambsquarters (26) 6
foxtail spp. (25) 7
johnsongrass (16)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- foxtail spp. included giant, green and yellow foxtail.
morningglory spp. included ivyleaf morningglory.
pigweed spp. included redroot and smooth pigweed and Powell amaranth.

8. Top 5 Weeds in Cotton MOST COMMON MOST TROUBLESOME
(27 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Palmer amaranth (25)* 2
morningglory spp. (21) 3
large crabgrass (10) 4
horseweed (marestail) (9)
Urochloa spp. (9) 1
Palmer amaranth (27)* 2
morningglory spp. (25) 3
horseweed (marestail) (10) 4
kochia (4)
Russian-thistle (4)
large crabgrass (4)
prickly sida (4)
Urochloa spp. (4)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- morningglory spp. included ivyleaf, pitted, tall and sharppod morningglory.
Urochloa spp. included Texas and browntop millet and broadleaf signalgrass.

9. Top 5 Weeds in Forestry MOST COMMON MOST TROUBLESOME
(14 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Mary’s-grass (Japanese stiltgrass) (5)*
honeysuckle spp. (5) 3
Japanese barberry (3)
Elaeagnus spp. (3)
kudzu (3)
multiflora rose (3) 1
Mary’s-grass (Japanese stiltgrass) (5)* 2
honeysuckle spp. (4) 3
barberry spp. (3)
privet spp. (3)
kudzu (3)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- honeysuckle spp. included Japanese and Amur honeysuckle.
barberry spp. included Japanese and European barberry.
Elaeagnus spp. included autumn-olive and thorny olive.
privet spp. included Chinese privet.

10. Top 5 Weeds in Fruits & Nuts
(17 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
red sorrel (7)* 2
quackgrass (4) 3
goldenrod spp. (3) 4
Tie among 15 species (2) 1
spreading dogbane (4)*
quackgrass (4)
red sorrel (4)
Rubus spp. (4)
eastern poison-ivy (4)
fescue spp. (4)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- Rubus spp. included bristly and southern dewberry.

11. Top 6 Weeds in Natural Areas- Parks, Refuges
(52 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Bromus spp. (17)* 2
Canada thistle (12) 3
garlic mustard (8) 4
Elaeagnus spp. (7)
multiflora rose (7) 6
Tie among 4 species (6) 1
Bromus spp. (12)*
toadflax spp. (12) 3
knapweed spp. (11) 4
Canada thistle (10) 5
leafy spurge (7)
cogongrass (7)
Japanese knotweed (7)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
Bromus spp. included downy brome (cheatgrass), and smooth and red brome.
toadflax spp. included yellow and Dalmatian toadflax.
knapweed spp. included Russian, spotted, and diffuse knapweed and yellow starthistle.
Elaeagnus spp. included autumn-olive and Russian-olive.

12. Top 5 Weeds in Ornamentals
(21 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Chamaesyce spp. (14)* 2
woodsorrel spp. (13) 3
crabgrass spp. (11) 4
bittercress spp. (8) 5
common chickweed (6) 1
nutsedge spp. (12)* 2
Chamaesyce spp. (8) 3
bittercress spp. (6)
woodsorrel spp. (6) 5
Canada thistle (5)
Phyllanthus spp. (5)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- Chamaesyce spp. included prostrate and spotted spurge.
nutsedge spp. included yellow and purple nutsedge.
woodsorrel spp. included creeping and yellow woodsorrel.
crabgrass spp. included large crabgrass.
bittercress spp. included flexuous, hairy, and little bittercress.
Phyllanthus spp. included chamber-bitter and long-stalked Phyllanthus.

13. Top 6 Weeds in Pasture, Rangeland, other Hay
(54 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Canada thistle (19)* 2
Bromus spp. (14) 3
Carduus spp. (13) 4
common ragweed (8)
leafy spurge (8)
knapweed spp. (8) 1
Canada thistle (18)* 2
leafy spurge (12)
toadflax spp. (12)
knapweed spp. (12) 5
Bromus spp. (10) 6
Tie among 2 species (9)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
Bromus spp. included Japanese, red, and downy brome (cheatgrass), and rescuegrass.
toadflax spp. included yellow and Dalmatian toadflax.
Carduus spp. included musk, plumeless, and Italian thistle.
knapweed spp. included Russian, spotted and diffuse knapweed and yellow starthistle.

14. Top 4 Weeds in Peanuts MOST COMMON MOST TROUBLESOME
(6 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Palmer amaranth (6)*
nutsedge spp. (6) 3
Texas millet (5) 4
morningglory spp. (4) 1
nutsedge spp. (7)* 2
Palmer amaranth (4)
Texas millet (4) 4
morningglory spp. (3)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- nutsedge spp. included yellow and purple nutsedge.

15. Top 5 Weeds in Pulse Crops
(15 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
mustard spp. (9)*
foxtail spp. (9) 3
kochia (8) 4
pigweed spp. (7)
wild buckwheat (7) 1
Galium spp. (8)*
kochia (8) 3
common lambsquarters (7) 4
Canada thistle (6) 5
pigweed spp. (5)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- mustard spp. included wild mustard, rapeseed (volunteer canola) and field pennycress.
- Galium spp. included catchweed bedstraw (cleavers) and false cleavers.
- foxtail spp. included green, giant, and yellow foxtail.
pigweed spp. included redroot pigweed and Powell amaranth.

16. Top 4 Weeds in Rice MOST COMMON MOST TROUBLESOME
(6 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Cyperus spp. (6)* 2
barnyardgrass (5)
Amazon sprangletop (5)
red rice biotypes (5) 1
sprangletop spp. (6)*
red rice biotypes (6) 3
Cyperus spp. (5) 4
barnyardgrass (4)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- Cyperus spp. included yellow nutsedge, rice flatsedge and annual sedge.
sprangletop spp. included Amazon and Nealley’s sprangletop.

17. Top 5 Weeds in Right-Of-Ways
(30 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Canada thistle (11)* 2
common ragweed (6) 3
kochia (5) 4
poison-hemlock (4)
Salsola spp. (4)
johnsongrass (4)
dandelion (4) 1
Canada thistle (11)* 2
johnsongrass (6) 3
Japanese knotweed (5)
knapweed spp. (5) 5
Tie among 3 species (4)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
knapweed spp. included Russian, spotted and diffuse knapweed and yellow starthistle.
Salsola spp. included Russian-thistle, barbwire Russian-thistle, and Salsola australis.

18. Top 5 Weeds in Sorghum MOST COMMON MOST TROUBLESOME
(17 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
Palmer amaranth (14)* 2
large crabgrass (8)
foxtail spp. (8) 4
morningglory spp. (6)
johnsongrass (6)
Urochloa spp. (6) 1
johnsongrass (11)* 2
Palmer amaranth (10)
Urochloa spp. (10) 4
crabgrass spp. (6)
shattercane (6)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- foxtail spp. included green, giant and yellow foxtail.
- Urochloa spp. included Texas millet and broadleaf signalgrass.
morningglory spp. included sharppod morningglory.
crabgrass spp. included large crabgrass.

19. Top 7 Weeds in Soybeans MOST COMMON MOST TROUBLESOME
(90 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
foxtail spp. (56)* 2
common lambsquarters (49) 3
waterhemp (34)
horseweed (marestail) (34) 5
common ragweed (31) 6
pigweed spp. (30) 7
morningglory spp. (28) 1
horseweed (marestail) (48)* 2
Palmer amaranth (46) 3
waterhemp (44) 4
giant ragweed (36) 5
common lambsquarters (33) 6
morningglory spp. (32) 7
common ragweed (29)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- foxtail spp. included giant, green and yellow foxtail.
- pigweed spp. included redroot and smooth pigweed and Powell amaranth.
- morningglory spp. included ivyleaf, pitted, and tall morningglory.

20. Top 5 Weeds in Spring Cereal Grains
(31 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
wild oat (22)* 2
wild buckwheat (20) 3
kochia (16) 4
foxtail spp. (15) 5
common lambsquarters (14) 1
wild oat (23)* 2
kochia (18) 3
wild buckwheat (15) 4
Canada thistle (11)
foxtail spp. (11)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- foxtail spp. included green and yellow foxtail.

21. Top 4 Weeds in Sugarbeets
(7 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
common lambsquarters (7)* 2
pigweed spp. (6) 3
common ragweed (4) 4
Tie among 3 species (3) 1
common lambsquarters (6)* 2
common ragweed (5) 3
pigweed spp. (4)
kochia (4)
velvetleaf (4)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
- pigweed spp. included redroot pigweed and Powell amaranth.

22. Top 5 Weeds in Turf MOST COMMON MOST TROUBLESOME
(32 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
crabgrass spp. (33)* 2
dandelion (18)
clover spp. (18) 4
annual bluegrass (17) 5
plantain spp. (13) 1
nutsedge spp. (18)* 2
Paspalum spp. (15) 3
common blue violet (13)
annual bluegrass (13) 5
ground ivy (10)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
crabgrass spp. included large and smooth crabgrass.
nutsedge spp. included yellow and purple nutsedge.
Paspalum spp. included dallisgrass, thin paspalum and bahiagrass.
- clover spp. included white clover.
- plantain spp. included buckhorn and broadleaf plantain.

23. Top 3 Weeds in Vegetables- Cole Crops, Greens
(6 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
common lambsquarters (4)*
mustard spp. (4) 2
pigweed spp. (3) 1
mustard spp. (4)* 2
nutsedge spp. (3)
common lambsquarters (3)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
mustard spp. included shepherd’s-purse and wild radish.
pigweed spp. included redroot pigweed.
nutsedge spp. included yellow nutsedge.

24. Top 4 Weeds in Vegetables- Cucurbits
(7 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
pigweed spp. (5)*
crabgrass spp. (5) 3
common lambsquarters (4)
nutsedge spp. (4) 1
nutsedge spp. (7)* 2
pigweed spp. (4) 3
Tie among 5 species (3)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
pigweed spp. included redroot and smooth pigweed.
nutsedge spp. included yellow and purple nutsedge.
crabgrass spp. included large crabgrass.

25. Top 4 Weeds in Vegetables- Fruiting
(8 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
nightshade spp. (5)* 2
pigweed spp. (4)
barnyardgrass (4) 4
Tie among 4 species (3) 1
nutsedge spp. (7)* 2
nightshade spp. (6) 3
Tie among 5 species (2)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
nightshade spp. included eastern black, black and hairy nightshade.
nutsedge spp. included yellow and purple nutsedge.
pigweed spp. included redroot pigweed.

26. Top 5 Weeds in Vegetables- Other
(18 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
pigweed spp. (13)*
common lambsquarters (13) 3
foxtail spp. (6) 4
barnyardgrass (5) 5
large crabgrass (4) 1
pigweed spp. (7)* 2
nutsedge spp. (6) 3
common lambsquarters (5) 4
Tie among 6 species (4)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
pigweed spp. included redroot and smooth pigweed and Powell amaranth.
nutsedge spp. included yellow nutsedge.
foxtail spp. included green, giant, and yellow foxtail.

27. Top 6 Weeds in Winter Cereal Grains
(34 survey respondents)
MOST
COMMON
MOST
TROUBLESOME 1
mustard spp. (22)* 2
Bromus spp. (18) 3
Lamium spp. (17) 4
kochia (11) 5
common chickweed (10) 6
wild oat (9) 1
Bromus spp. (22)* 2
Italian ryegrass (13) 3
kochia (11) 4
common chickweed (9) 5
cereal (feral) rye (8) 6
jointed goatgrass (7)
* number of survey respondents who listed the weed species as one of their top 5 weeds in this crop.
mustard spp. included field pennycress, rapeseed (volunteer canola), wild, blue and tumble mustard, flixweed, tansymustard spp. and shepherd’s-purse.
Bromus spp. included downy brome (cheatgrass), cheat and rescuegrass.
Lamium spp. included henbit and purple deadnettle.

28. Top 10 Most Common Weeds among all Terrestrial Crop and Non-crop Areas
(606 total survey respondents)
MOST
COMMON
* number of survey respondents who listed the weed species as one of their top 5 weeds.
foxtail spp. included green, giant, and yellow foxtail.
crabgrass spp. included large, smooth and southern crabgrass.
pigweed spp. included redroot and smooth pigweed and Powell amaranth.
morningglory spp. included ivyleaf, pitted, tall, and sharppod morningglory.
mustard spp. included rapeseed (volunteer canola), wild, black, white, tumble, African, hedge and blue mustard, shepherd’s-purse, flixweed, tansymustard spp., wild radish, field pennycress and London rocket. 1
foxtail spp. (184)* 2
common lambsquarters (163) 3
crabgrass spp. (123) 4
pigweed spp. (122) 5
Palmer amaranth (96) 6
morningglory spp. (92) 7
common ragweed (89) 8
mustard spp. (88) 9
kochia (85) 10
waterhemp (73)

29. Top 10 Most Common Weeds among all Aquatic Areas
(84 total survey respondents)
MOST
COMMON
* number of survey respondents who listed the weed species as one of their top 5 weeds.
Myriophyllum spp. included Eurasian, variable and northern watermilfoil, watermilfoil hybrids, and parrotfeather.
Potamogeton spp. included curlyleaf, Illinois, leafy, American, Richardson’s, and floatingleaf pondweed.
Najas spp. included southern, brittleleaf, slender and hollyleaf naiad.
Lemna spp. included common duckweed.
Ludwigia spp. included creeping and Uruguay waterprimrose and primrose-willow.
Typha spp. included common and blue cattail
algae spp. included filamentous and planktonic algae and “harmful algal blooms”. 1
Myriophyllum spp.(45)* 2
Potamogeton spp. (43) 3
hydrilla (24) 4
Najas spp. (18) 5
waterhyacinth (15)
Lemna spp. (15)
Ludwigia spp. (15)
Typha spp. (15) 9
algae spp. (14)
coontail (14)

30. (606 total survey respondents)
Top 10 Most Troublesome Weeds among all Terrestrial Crop and Non-crop Areas
(606 total survey respondents)
MOST
TROUBLESOME 1
Palmer amaranth (127)* 2
morningglory spp. (101) 3
common lambsquarters (97) 4
horseweed (marestail) (94) 5
waterhemp (92) 6
nutsedge spp. (90)
Canada thistle (90) 8
kochia (89) 9
giant ragweed (71)
foxtail spp. (70)
* number of survey respondents who listed the weed species as one of their top 5 weeds.
morningglory spp. included ivyleaf, pitted, tall, and sharppod morningglory.
nutsedge spp. included yellow and purple nutsedge.
foxtail spp. included giant, green, and yellow foxtail.

31. Top 10 Most Troublesome Weeds among all Aquatic Areas
(84 total survey respondents)
MOST
TROUBLESOME
* number of survey respondents who listed the weed species as one of their top 5 weeds.
Myriophyllum spp. included Eurasian, variable and northern watermilfoil, watermilfoil hybrids, and parrotfeather.
Potamogeton spp. included curlyleaf, Illinois, leafy, American and Richardson’s pondweed
Salvinia spp. included giant salvinia and water fern.
algae spp. included filamentous and planktonic algae and “harmful algal blooms”.
Lemna spp. included common duckweed.
Ludwigia spp. included creeping and Uruguay waterprimrose and primrose-willow. 1
Myriophyllum spp. (47)* 2
hydrilla (45) 3
Potamogeton spp. (26) 4
waterhyacinth (19) 5
Salvinia spp. (14) 6
algae spp. (13)
Lemna spp. (13)
Ludwigia spp. (13) 9
waterlettuce (12) 10
Tie among 2 species (9)