You cannot fill that crater - it's supposed to be empty to hold rainwater.

But you can hide it with something. If you plant tall reeds and cattails, you could pretend there's a pond in there.

Or, just make yourself a sign that says "UFO Landing Sight. Admission 25 cents."

That's what I'm asking. What could I plant in there that would be attractive, and camoflage it? Are there any pretty flowering plants that are tall? Someone even mentioned Rosa Rugosa. We live near the beach near Plymouth MA and the Cape.

Tall? Ya wanna plant a hedge?

OK, rosa rugosa. Camellia, rhododendron, forsythia, bluberries, buddleia, holly (no flowers, but nice berries), viburnum, spirea.

Or plant an evergreen hedge and put some pretty perennials in front of the hedge.

i would not put cattails in there --- there are lovely native plant mixes of tall grasses and wildflowers made specifically for detention areas. a detention area when planted properly makes a beautiful wildflower garden. and the native plants are an asset to stormwater control and water quality. their extensive root system helps dry out the bottom. do an internet search on "rain garden" there is tons of information out there.