Junk grass are usually grassy (Called Moncots-multiple stems) weeds that invade a lawn and take away the uniform appearance that’s vital to having a nice lawn.
These junk grasses get into a lawn:

1. From the soil

2. From birds/wind

3. By mowing services

These junk grasses cannot be killed with the traditional weed killers

Some Junk grasses are:

1.Goose grass-Large clump grass. Ruins uniformed appearance

2. Quack grass-Large Clump grass. Ruins uniformed appearance

3. Sedge- Upright tall grass. Ruins uniformed appearance.

4. Nimblewill-Dies out in patches during the summer.

5. Poa-annual bluegrass-Dies out in patches. Pulls up easily, often mistaken for grub damage.

6. Zoysa Grass-A “Warm season” grass (See picture) Goes dormant in the fall. Stays dormant until the following June. (See picture).

If you have only a small amount in your lawn, then it can be killed with vinegar. If you have a very large percent then your lawn must be renovated. (See Lawn Renovation)