Light green, wide blade, small clumps in my sodded lawn. It is faster growing than the other grass. Sod is 2 years old and has had regular lawn care treatments, 5 apps a year. It has already had 1 app of dimension 12-0-0 put down. I do not believe it was overseeded with anything, just sod. I believe the 3rd images if even a different variety because it’s a larger clump and darker green??
Frederick County Maryland
The lighter green grass shown in your first photo looks like it might be roughstalk bluegrass (Poa trivialis). https://extension.umd.edu/hgic/topics/roughstalk-bluegrass
In photos #2 and #3, those look like orchardgrass. Orchardgrass has a wider leaf, bluish color, flat stem, and a long ligule (membrane between the stem and leaf). Here is information about it and what you can do. https://extension.umd.edu/hgic/topics/orchardgrass
Poa trivialis is a perennial grass which spreads by stolons and seeds. It is challenging to deal with since it cannot be effectively controlled by any selective herbicides currently on the market. Later in the season, it blends in with fescue grass.We've been seeing more reports of roughstalk bluegrass and total control of it is very doubtful. You could just decide to leave it and treat it as part of the mixture of grass. If you want to manage it, the best option is to use a systemic herbicide, namely one containing the ingredient glyphosate. This will leave dead patches that will have to be reseeded. The best time for overseeding is in the fall.
The best defense against weeds is to thicken the turf by following good cultural practices: soil testing, fertilization based on soil test results and UMD guidelines (https://extension.umd.edu/hgic/topics/lawn-fertilizing), overseeding, and "mowing high." Mowing too short often results in weed problems.
Refer to our information on lawn care best practices and weed management.