The roots are generally fibrous and branching with an extensive underground network or surface stems. Thus, grasses prevent soil erosion. See also the information on tree and weed pollens. Poa annua . Seedlings mature in the fall, overwinter in a vegetative state, and produce seed in late spring and early summer.
Annual bluegrass is a prolific seed producer.
Annual bluegrass grows well even in cool conditions and short days but the Summer heat may kill it. Often used on golfcourses due to its robust nature. Also called sweet vernal or simply vernal grass. A genus of about 4 four species of fragrant annual and perennial grasses. Thin, flat leaves contain coumarin which is released as a sweet scent when it is cut for hay.