Hello Linda,

Berrien County has areas that are 6a, 6b and 7a on the USDA hardiness zone map.

Your choices for short ornamental grasses for full shade are not plentiful. Ornamental grasses are typically sun loving plants. Fortunately, Dr. Art Cameron who curates Ornamental Grass species at MSU recommends 4 grasses for shade and all are relatively short in stature. He lists these as shade “tolerant.” I am afraid your shade is pretty dense, so I would try a few plantings and see how they do and fine tune from there.

Carex (Sedges) - many American species

Chasmanthium latifolium

Hakonochloa macra ‘All Gold’ is a great cultivar

Luzula sylvestris

https://www.canr.msu.edu/hrt/uploads/534/79846/2010-Ornamental-grasses-for-Michigan-Art-Cameron.pdf

https://www.extension.iastate.edu/news/yard-and-garden-ornamental-grasses

You mention mondo grass, but it is typically a more warm climate variety. If you can find a mondo grass variety for your hardiness zone, you could try that. Art Cameron has had success with black mondo grass overwintering in central Michigan, but the dark foliage may not be the aesthetic you desire unless you plant it with a brighter foliage for contrast.

https://www.canr.msu.edu/uploads/resources/pdfs/ornamentalgrasses.pdf

There is surprisingly little information on the best time to plant ornamental grasses, but the research is pretty unanimous in performing root divisions in the spring, so I would say that spring planting is probably preferrable. You will probably have better plant choices in the spring rather than now. In general, perennials are most successful if planted in the spring, since it gives them a long time to develop roots that anchor them into the soil. If this does not occur, the freeze/thaw cycles of winter can literally pop the plants out of the soil which will ultimately kill them.

https://www.extension.iastate.edu/news/2007/oct/082701.htm

Hope this helps.

Thank you. The information is very helpful.

Good luck gardening!