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Johnsongrass

Description

Johnsongrass is not a common weed in turf situations. It is frequently found on roadsides, but is also found in pastures and disturbed fields. It does not grow well in frequent, close mowing situations. As an adult plant, johnsongrass is characterized by its dense growth habit, with stems that can reach 6 ft in height. The leaf blades are rough, and the prominent white raised midveins that run the length of the leaf are distinctive. The seedhead is purple.

Cultural Control

Perennial grass weeds are not desirable as turfgrass species under any conditions. Therefore, every effort should be made to prevent these weedy grasses from becoming established in turf, as selective control measures are usually difficult. Selection of adapted turfgrass species and cultivars and the use of cultural practices are important in minimizing weedy grass encroachment and competition. Management practices include (1) mowing at the recommended height for the selected turfgrass and removing clippings when seedheads of grassy weeds are present; (2) applying the proper amount of nitrogen at the correct time according to the turfgrass present; and (3) using soil tests to determine needed nutrients and lime.

Presentations

Publications

Species Data

Seedhead/Flower

panicle; seedhead is often purplish

johnsongrass
johnsongrass
johnsongrass
p1080734 johnsongrass
p1080734 johnsongrass
p1080734 johnsongrass
seedhead2
seedhead2
seedhead2
Vernation type

rolled

p1010269
p1010269
p1010269
vernation2
vernation2
vernation2
Ligule Type

membranous; fine hairs

leafhairs
leafhairs
leafhairs
ligule4
ligule4
ligule4
ligule5
ligule5
ligule5
Growth Season/Life Cycle

perennial weed

johnsongrass
johnsongrass
johnsongrass
Auricle type

absent

leafhairs
leafhairs
leafhairs
ligule4
ligule4
ligule4
ligule5
ligule5
ligule5
sheathmargin
sheathmargin
sheathmargin
Leaf blade tip shape

sharp-pointed

leafblade
leafblade
leafblade
Leaf blade width

0.4 - 1.2 inches (10 to 30 mm) wide

leafblade
leafblade
leafblade
midrib
midrib
midrib
Stolon Presence

absent

Rhizome Presence

present

Collar Type

continuous

collar
collar
collar
collar2
collar2
collar2
Sheath Margin

open

sheath
sheath
sheath
sheathmargin
sheathmargin
sheathmargin
Sheath Type

round to somewhat flattened