Carex pennsylvanica

Deer & Drought Proof Grass for the 'No Mow Lawn'

Carex pennsylvanica has slightly arching, fine-textured green blades that spreading slowly to create a lush semi-evergreen carpet growing 8-10" high. Clusters of brown seed capsules appear in spring. Sedges are close relatives of grasses and look a lot like them and can function like a traditional lawn.

Carex pennsylvanica adapts to various soils, including loam, sandy, or acidic rich and thrives in DRY and MOIST SHADE and competition from tree roots. Carex will also grow in full sun, but you'll need to provide some moisture.

Carex pannsylvanica binds the soil with its dense roots making it ideal for shady slopes.

This low maintenance shade groundcover is great for areas where one wants a lawn feel - but growing turf isn't feasible.

What is a bio retention area in this instance? Is it a septic field? Or an area that floods regularly but is planted? Carex pensylvanica AKA Pennsylvania sedge isn’t happy in areas that flood though there are other sedges that are happy with wet feet. Where are you? It won’t be happy in all parts of the US. Here is its native US range.

https://plants.usda.gov/core/profile?symbol=cape6

Carex pensylvanica (note spelling only has one n at the beginning) doesn’t like flooding IME and as Jan Moyer said, it will need watering if in full sun as most septic fields are, as well as during the establishment phase regardless. It will also need removal of any woody weeds such as blackberry bushes and maple seedlings a couple of times a year since mowing (the typical way to control woody plants in field areas) doesn’t improve appearance. I have a fairly extensive stand growing native on my property and really like it, though due to poor soil and no watering, it isn’t as lush as the photo above.

And it being a Carex it's a sedge of course instead of a grass. If in fact the two photos are showing the same plant.

Carex is a rather large genus and there are a number of species that will provide a similar effect as shown in the photo, all natives. Which one you might want to employ for this purpose would be dependent on where exactly you are located.