beneficial perennials in Zone 4

I am from Minnesota. Does anyone have any recommendations for perennial plants that do well in this area (Zone 4), are relatively easy/cheap to establish, and are multifunctional (e.g. edible, provide mulch material, attract beneficial insects, etc.)?

I have a small urban lot that I garden in vegetables that I am looking to incorporate with an outer ring of perennial plants, to act as a visual and physical buffer. My hope is to have perennial plantings that reduce nutrient runoff, attract beneficial insects, create compostable biomass/mulch, are edible, and are pretty to boot.

Thanks in advance!

I am in North Central Michigan zone 4/5 (depending on the year and the winter)..at the end of this post you'll see a link to my blog.. I'm not guaranteeing everything on my PLANT LIST will survive at your place, or even at mine..I experiement. Some thrive and survive and some struggle and some just out and out die.

At the bottom of my plant list is a list of things I've ordered for 2012 planting, the others have been planted in previous years or grew here as natives, bird planted or whatever.

I am also changing most of my property over as much as possible to perennials or permanent plantings as I am able..however, I do also use self seeders and biennials to a large extent here.

I also tend to use a few season extenders here and find new ways to overwinter crops so that they can be saved from season to season..but I'm not fond of replanting unless I have to (60 and ptl disabled)

I am a big weed eater..I love to eat things that grow around here on their own, and as my grandfather was a trapper and forager it comes natural in the genetics to forage for food, so I list as many as I can think of that can be foraged for in our neck of the woods, although I'm sure I skipped a few...see the blog

IF YOU LIKE Jerusalem Artichokes they are a really great plant I discovered 4 years ago, they provide emmense amounts of food and once you have them you don't have to replant them..I also eat a lot of ornamentals that grow like weeds here..some of my first spring salads are from simple things like violets and dames rocket that self seed all over our property, and I also allow the normal annuals to self seed, and generally can pick things like swiss chard all winter if I keep a few going in my greenhouse..(right now they are a bit wilted from the zero overnights)...my greenhouse is only heated slightly cause it sits where our underground pex is buried from the wood furnace to the houses..the air itself has no heat.

trying some new perennial veggies this year like good king henry, and also trying OP grains this year..(if I get the seeds I ordered, already had to reorder good king henry as first place was out).

good luck

wild leeks aka ramps

ostrich fern aka fiddleheads

rhubarb

chives

Crambe maritima - Sea Kale

Rumex acetosa - French Sorrell

my bountiful gardens order came today and the good king henry wasn't backorderd (although 2 other things were that I can live without)..was surprised at how fast they came too, you might want to try them for some perennial vegetables for your zone