This cool season annual grass is spreading forming a tufted habit with few advantages roots. It has lanced-shaped, light green flat leaves and the pyramidal flower head appears in autumn producing seed with a long dormancy factor. 

Hardiness zones 3 to 9 

Poa annua is naturally found in Europe on the coast on in the foot-hills of the mountains growing in moderately fertile moist well drained soils. It prefers an open sunny position but tolerates some shade and is drought and frost tolerant.

Winter Grass is normally regarded as a weed although it may be cultivated to form a lawn if closely cut as a turfgrass around 12mm (½in) tall. It has excellent shade tolerance and dominates open areas in turf grasses. It is suitable for coastal or low mountain regions and establishes in one season. ID 2502

Note:
The perennial forms, Poa annua Var. reptane is stoloniferous and has a prostrate habit with numerous tillers and advantageous roots. The seeds have no dormancy period. 

Poa (PO-ah) annua (an-U-ah)

Poaceae (poh_AY-see-ee)
Grass Family