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Annual bluegrass
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Bentgrass, creeping
Bermudagrass
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Bittersweet nightshade (European bittersweet)
Black medic
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Blue mustard (Purple mustard, Tenella mustard)
Brackenfern, western
Buffalobur
Bull thistle
Buttercup, creeping
Butterfly bush
Canada thistle
Catchweed bedstraw (Cleavers)
Catsear, common (False dandelion)
Chickweed, common and mouseear
Clover
Comfrey
Crabgrass
Creeping Jenny
Dandelion
Dock (Curly, Broadleaf)
Dodder
Downy brome (Cheatgrass, Downy chess)
Dwarf mistletoes
English daisy (Lawn daisy)
English ivy
Field bindweed (Wild morningglory)
Field pennycress (Fanweed)
Flixweed
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Garden loosestrife
Giant hogweed
Goldenrods
Ground ivy
Groundsel, common
Hawkweeds
Hedge bindweed
Henbit
Herb Robert (Robert geranium, stinky Bob)
Horsetails (Scouringrush)
Horseweed (Marestail)
Knapweeds
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Kochia
Lambsquarters, common
Lesser celandine
Liverworts
Mallow, common (Cheeseweed, Buttonweed)
Nightshades
Oxalis (Creeping woodsorrel)
Parrotfeather and Eurasian watermilfoil
Pineappleweed
Plantain (Broadleaf, Buckhorn)
Poison hemlock
Poison ivy and Poison oak
Pokeweed
Prickly lettuce (China lettuce)
Prostrate knotweed
Puncturevine (Tackweed, Goathead)
Purple deadnettle (Red deadnettle)
Purple loosestrife (Purple lythrum)
Purslane, common
Quackgrass
Red sorrel (Sheep sorrel)
Redroot pigweed (Rough pigweed)
Redstem filaree (Stork's bill, Crane's bill)
Reed canarygrass
Russian thistle (Tumbleweed)
Ryegrass, annual (Italian ryegrass)
Salsify (Goatsbeard)
Scotch broom
Shepherd's-purse
Smartweeds
Sowthistle, annual and perennial
Speedwells
Spurges (Prostrate spurges)
St. Johnswort, common (Goatweed, Klamathweed)
Stinging nettle
Tansy ragwort
Tumblemustard (Jim Hill mustard)
Velvetgrass (Common velvetgrass)
Velvetleaf
Water primrose
Waterhemlock, western
Wild carrot (Queen Anne's lace)
Yellow nutsedge
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Caption: Smartweed stem showing sheathing stipules at the nodes
Photo by: J.A. Kropf
Weeds : Smartweeds :
Polygonum spp.
(revision date: 4/7/2021)
Family: Polygonaceae
Cycle: Annual/Perennial
Plant Type: Broadleaf
Use Integrated Pest Management (IPM) for successful weed management.
Biology
Smartweeds are typically annual weeds with erect or spreading stems up to 3 feet long. The leaves are alternate, attaching to the erect or sprawling stems at enlarged nodes. Many smartweeds have a papery or clear membrane as part of the sheath where the petiole attaches to the stem. The small flowers of smartweeds are typically borne in short spikes or clusters arising in the leaf axils or at the tips of branches. Ladysthumb or spotted smartweed (P. persicaria) is one common species. Although most smartweed species have leaves are uniform in color, ladysthumb has a purplish spot or "thumbprint" at the center of each long, pointed leaf. Other species of interest include water smartweed (P. amphibium), a perennial which reproduces by seeds and from roots and is found in water or wet areas, and smartweed or water pepper (P. hydropiper), an annual species found in pastures, cultivated areas, and waste areas.
Habitat
Smartweeds can be weeds in cultivated areas, roadsides, waste areas, and other sites, depending on species. They are often found in moist sites including irrigated pastures.
Management Options
Non-Chemical Management
None recommended
Select non-chemical management options as your first choice!
Chemical Management
IMPORTANT:
Visit Home and Garden Fact Sheets for more information on using pesticides
NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.
Landscape areas
products containing dicamba
Turf areas
2,4-D + MCPP + dicamba
Bare ground areas
products containing dicamba
Images
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Caption: Smartweed stem showing sheathing stipules at the nodes
Photo by: J.A. Kropf
Caption: Smartweed
Photo by: T.W. Miller
Caption: Smartweed flowers
Photo by: T.W. Miller
Caption: Smartweed leaves
Photo by: J.A. Kropf