The only things that seem to grow in deep shade are dandelions and poison ivy and sugar maples. 
How shady is the area? Is there any direct sunlight hitting that area at all, even if it’s only a few hours per day? If you can get a few hours of sunlight per day, you have more choices.
For deep shade, hostas do okay under pine and spruce trees. There are some nice varieties available with different sizes and colors. I’m in zone 5 and I have some hostas around the base of my spruce trees, where very little bright sunlight penetrates. It’s okay; nothing exciting.
In USDA Zone 5 your options are rather limited, especially when it comes to flowering perennials in the shade.
When all is said and done, you might be better off going the mulch route. It’s attractive, low maintenance, and will function better than trying to find plants that will thrive and look good in a plant-hostile environment.
One thing you could do, if you’re so inclined, is to groom and mulch the area, and then bring in shade-tolerant annuals (impatiens, for example) in large, attractive containers. Container gardening is quite popular. It’s an art and a science and there are many articles and forums on the topic of gardening in containers.
Get large containers, lots of potting mix (generally you do NOT want to use top soil or compost), put the containers on dollies so you can move them around easily, plant the colorful flowers, and arrange them as you will. It would be nice if you could position them occasionally so they get a few hours of sun once or twice a week (impatiens don’t do well in full sun, but they need a little bit of sun here and there). You will also need to fertilize them every 2-3 weeks with an all-purpose, fast-acting fertilizer, diluted to the strength indicated for indoor plants. Outdoor-strength solution is too strong for container plants and they will get fertilizer burn.
You could also do plants like Caladiums which are grown from bulbs that can be purchased at almost any garden center. While not flowering plants, they have colorful leaves and they like the shade. You could save the bulbs every year (they only overwinter in the warmest zones) and replant them next year. But they’re economical enough that you could also by new bulbs if you don’t save them.
It could be gorgeous, but it is additional work and some extra expense. You need a place to store the containers over the winter and you should probably use new potting mix the next year.
I’ve been gardening in zone 5 for decades and have tried a number of things with plantings in deep shade. I’ve had very little luck. Unfortunately, we don’t live in the warm zones and don’t have a wide variety of zone-hardy plants to chose from.
Maybe some really creative person will have a better suggestion.