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Common Ragweed

Description

Common ragweed is a summer annual weed that emerges early in the spring. It is often found in cultivated areas, but also occurs in roadsides and landscapes. It prefers heavy soils as opposed to sandy soils, and does not tolerate heavy mowing. The deeply dissected leaves are arranged oppositely when young, and alternately in older parts of the plant. Leaves are hairy on both surfaces. Ragweed produces copious amounts of pollen in the late summer, and often causes allergy problems.

Cultural Control

Maintain a dense, actively growing turf through proper mowing, fertilizing, and watering practices. Mow at the proper height for your selected adapted turfgrass. Coring and traffic control reduce compaction and encourage desirable turfgrass competition. It is best to control this summer annual broadleaf weed in late spring or early summer because it is easier to control at this time and the turf will have a greater chance of recovering the areas previously occupied by weeds.

Chemical Control

Herbicide and Formulation
Amount of Formulation per 1,000 sq ft
Amount of Formulation per Acre
Pounds Active Ingredient per Acre

Preemergence and Postemergence Control

Herbicide and Formulation

mesotrione, MOA 27 (Tenacity) 4 SC

Amount of Formulation per 1,000 sq ft

0.092 to 0.183 fl oz

Amount of Formulation per Acre

4 to 8 fl oz

Pounds Active Ingredient per Acre

0.125 to 0.25

Precaution and Remarks

Use on residential turf, golf courses (not greens) and sod farms for pre- and postemergence weed control. Tolerant turfgrasses include St. Augustinegrass, centipedegrass, tall fescue, fine fescue, Kentucky bluegrass, and perennial ryegrass. Add a nonionic surfactant and repeat application after 2 to 3 weeks for improved postemergence control. Tank mix with Barricade 65 WG for extended preemergence grassy weed control. Can be applied at seeding to all tolerant grasses except fine fescue. After turf germination, wait 4 weeks or until turf has been mowed twice before making a postemergence application. Also controls henbit, chickweed, dandelion, white clover, Florida betony, Florida pusley, ground ivy, oxalis, wild violet, creeping bentgrass, and yellow nutsedge.

Preemergence and Postemergence Control

Herbicide and Formulation

sulfentrazone + prodiamine, MOA 14 + 3 (Echelon 4 SC) 4 SC

Amount of Formulation per 1,000 sq ft

0.184 to 0.826 fl oz

Amount of Formulation per Acre

0.5 to 2.25 pt

Pounds Active Ingredient per Acre

0.25 to 1.125

Precaution and Remarks

For use in residential and institutional lawns, athletic fields, sod farms, golf course fairways and roughs, roadsides, utility right-of-ways, railways, and industrial areas. Apply to turf following a second mowing if a good root system has been established. Apply up to 12 fluid ounces per acre to bentgrass at 0.5 inches or higher, fine fescue, and perennial ryegrass. Apply 18 to 24 fluid ounces per acre to perennial bluegrass, tall fescue, and all warm season grasses except St. Augustinegrass (do not apply) and bermudagrass (apply 18 to 36 fluid ounces per acre). For sod production, apply 6 months after establishment, and do not harvest within 3 months. Do not apply with adjuvants or surfactants. Echelon should not be applied to cool-season turf with N-containing fertilizers unless some short-term discoloration is tolerable.

Presentations

Publications

Species Data

Growth Season/Life Cycle

summer annual weed

Growth Habit

upright

autopsy2
autopsy2
autopsy2
leafarrangement
leafarrangement
leafarrangement
ragweed
ragweed
ragweed
Leaflet Number

one

hairystem
hairystem
hairystem
leaf
leaf
leaf
leafarrangement
leafarrangement
leafarrangement
p1110725 ragweed
p1110725 ragweed
p1110725 ragweed
Leaf Margin

lobed

hairystem
hairystem
hairystem
leaf
leaf
leaf
leafarrangement
leafarrangement
leafarrangement
Leaf Hairs

upper/lower surface

leaf
leaf
leaf
Leaf/Leaflet Shape

oval/egg-shaped/elliptical

hairystem
hairystem
hairystem
leaf
leaf
leaf
leafarrangement
leafarrangement
leafarrangement
p1110725 ragweed
p1110725 ragweed
p1110725 ragweed
Leaf Width

1 inch to greater than 2 inches

hairystem
hairystem
hairystem
leaf
leaf
leaf
leafarrangement
leafarrangement
leafarrangement
Leaf Venation

pinnate

hairystem
hairystem
hairystem
leaf
leaf
leaf
leafarrangement
leafarrangement
leafarrangement
p1110725 ragweed
p1110725 ragweed
p1110725 ragweed
Leaf Arrangement

leaves are arranged oppositely when young, and alternately in older parts of the plant

hairystem
hairystem
hairystem
leafarrangement
leafarrangement
leafarrangement
p1110725 ragweed
p1110725 ragweed
p1110725 ragweed
Root Type

taproot with many root hairs

roots2
roots2
roots2
Flower Color

inconspicuous

p1120794 ragweed
p1120794 ragweed
p1120794 ragweed