I'd like to plant some edible perennials around my dogwood. I'm guessing the biggest limitation is partial sunlight. What would work best?
I'd forget growing veggies, flicker. They need sun to make those reproductive organs or rather the veggies that will FEED us. Keep veggies in the sun. Even lettuce would be wimpy without the sun.
A great idea would be impatiens. Floriferous, thrives well in shade for a flowering plant. An annual. Not perennial. A perennial would be Japanese Spurge. No food, sorry. To get plants thriving IN SHADE takes genetics.
A little tree trying to get a foot hold in its new environment will NOT like the competition with plants beneath its canopy.
Food crops need the sun!
There are plenty of vegetables that will grow well in partial shade, but your requirement for perennials is more problematic, and harvesting shade-tolerant root vegetables like carrots, leeks, or potatoes would repeatedly disturb the tree roots.
A few suggestions would be mint, rhubarb, or asparagus. If you also want flowers, hostas are related to asparagus and have edible leaves - though the slugs may eat them before you get the chance.
If you want to try something more radical, just grow nettles, which are tasty and nutritious. Cooking them removes the "sting." You can find plenty of recipes on the web.
If you want fruit, brambles will grow perfectly well in shade, but keeping them under control might be a problem. Soft fruit like raspberries would also be an option, though only 5 feet of headroom is a bit limiting.