Page 138 - AG 7-2011 Revised 2016

Photo Courtesy of PBI/Gordon Corp. Annual Bluegrass
(Poa Annua)
Drawing by Andrew Schaible
Annual bluegrass contains both annual and perennial species.
Annual bluegrass forms dense patches that can withstand low
mowing heights. Annual bluegrass has a boat-shaped tip,
folded in the bud. The ligule is membranous and auricles are
absent.

Annual bluegrass has a small panicle seedhead. Germination
occurs in late summer and early spring.

Annual Bluegrass is found throughout the United States and
Canada.

Immature Stage

Integrated Pest Management Control Recommendations
Cultural Practices:
Annual bluegrass cannot be controlled culturally. Both annual and perennial species of annual bluegrass exist,
depending on where it’s developing. Most annual bluegrass on greens is of the perennial species, while the
annual species develops in fairways and lawn type settings. Both will fade out with hot summer temperatures. The
perennial species will develop from the crowns of existing plants and seeds, while the annual species develop
from germinating seeds in the fall. Annual bluegrass can adapt to all cutting heights. The seedhead will also
develop under all cutting heights. Annual bluegrass excels with high fertility and irrigation.

Herbicide Use:
Make a preemergent application in the fall and spring to prevent germination of annual bluegrass.

Johnson Grass
(Sorghum halepense)
Johnson grass is a tall, coarse, grass with stout rhizomes. It grows
in dense clumps or nearly solid stands and can reach 8 feet in
height.

Leaves are smooth, 6-20 inches (15.2-50.8 cm) long, and have a
white midvein. Stems are pink to rusty red near the base. Panicles
are large, loosely branched, purplish, and hairy.

Spikelets occur in pairs or threes and each has a conspicuous
awn. Seeds are reddish-brown and nearly 1/8 inch (0.3 cm) long.

Immature Stage

Integrated Pest Management Control Recommendations
Cultural Practices:
Prevent production and spread of seed. Destroy seedlings before rhizomes are formed. Weaken and kill existing
rhizomes. Control new infestations as they appear.

132