The leaves are a soft round shape and I've yet to see a spot of disease or a bug bite in all the years they have been out in the shade bed.
What's amusing about them is that they move around the bed, travelling from one side of that paver path in the photo to the other. I asked them why but they gave no response.
Cold hardy in zones 3 to 8 or 9 means that gardeners in most parts of the globe can be successful with them. Plus, they are a native so they behave. They max out at about 1.5 feet tall and die to the ground with summer's heat.
They can be inter-planted with ferns and hostas since they are gone when those plants are showing their stuff.
The clumps can be divided early in the spring or root cuttings can be made when the plants are dormant.
Ephemeral plants have short cycles. A spring ephemeral is one that comes up quickly in the spring and dies back to the ground before you know it. Other native spring ephemerals for the shade garden include Blood Root and False Rue Anemone.