What is the primary characteristic of annual bluegrass?

Annual bluegrass, known scientifically as Poa annua, is distinctively characterized by its small open-panicle seedheads. This feature is a key identification trait of the species and is significant for managing this turfgrass within cool-season areas. The seedheads emerge from the plant in a distinctive way, often creating a unique visual that sets it apart from other grasses.

In addition to the seedhead trait, annual bluegrass has a bunch-type growth habit and can germinate throughout the year under suitable conditions, contributing to its presence in various lawn and turf areas. Its propensity to flower and produce seed rapidly can lead to its dominance in turf situations when conditions are favorable.

The other characteristics in the choices do not accurately reflect annual bluegrass. For example, while annual bluegrass can form a certain degree of density, it is not primarily known for forming a dense mat like some other grasses, nor does it thrive in dry conditions—rather, it prefers moist environments. Additionally, annual bluegrass is a cool-season grass that grows mainly during the spring and fall, not primarily during the summer, which is when many warm-season grasses would be more dominant.