These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area. Chances are these are perennial grassy weeds, which are difficult to manage in lawns. Many perennial grass weeds, such as tall fescue, are desirable grasses when growing by themselves but become weeds when mixed in Kentucky bluegrass lawns because of different texture, color, or growth habit.
Tall fescue is coarser and grows in mounded clumps.
Creeping bentgrass appears as patches of finer grass, usually lighter in color. Zoysiagrass appears as thick patches of dormant grass for much of spring and fall in bluegrass lawns. One way to distinguish perennial grasses from annuals is the time of the year established plants are present. Crabgrass plants are not yet visible this season. Most annuals die off quickly in fall, but perennials do not.