Neither wild ginger nor crested iris are your average groundcover, but both are reliable in shade that is not too dense. They cover the ground quite well, and don’t get too tall.
The crested iris, Iris cristata, bloom at the beginning of May for a week or so, and they are quietly spectacular. The rest of the year they are just a nice green groundcover that seems to be pretty sturdy, although they fade out where the shade gets too dense and sulk if it gets too dry.
Wild ginger, Asarum canadense, also blooms in the spring, but their audience is ants. They have a really neat little flower, but you would have to get down on your hands and knees to see them—a good exercise for the small child in your life who finds hidden treasures exciting. Wild ginger needs more shade than the crested iris, and at least as much water. Any plants that crawl beyond their shade get cooked in the summer sun. Wild ginger is native to most of the eastern half of the continent in rich woods. The status of crested irises is another story, however.
When I bought a small pot crested of irises several years ago at a plant sale, the seller told me that they are Michigan natives. She was misinformed and so I was too, until someone said something to me that inspired me to check. This is a screen capture from the USDA’s NRCS plants database:
Those areas are, for the most part, hilly or mountainous (at least to an easterner). How did this little plant skip over almost all of Pennsylvania, New Jersey, New York, and a chunk of New England to land in the northeastern corner of Massachusetts? It is listed as an endangered plant in both Maryland and Pennsylvania.
Are they delicate? That first pot of irises did not reappear the following spring, so I bought another potful and planted them. The following year both pots came up. My little corner of the planet is on a small downtown lot in a small city in southeast Michigan, where one could imagine from that USDA map that irises with that kind of native range might find at least the severe winters to be too severe, but not that I can see. They are very happy—and not delicate at all.
They are not too fussy. They prefer some shade, but that may be because they prefer to be well hydrated. The sunniest of the spots I have them in is considerably wetter than much of the rest of the yard and they are looking very ambitious.
Most of the other crested irises in my yard make up a groundcover border in fairly shady areas. The plants look quite different in the shade—lankier, and like they are all running for the border—at least at this point—but they will leaf out quite respectably.
The irises have had a little green showing since at least mid-March, but the wild ginger just started peeking in the last couple of days. Today, it is definitely visible.
These plants don’t look like much yet, but a bed of these popping out look like little fish checking for low-flying bugs in a pond. Later, the leaves grow relatively large and heart shaped. As long as the plants remain in the shade, they are very nice-looking and reliable.