Yea natives only is a very weird challege. We oddly boxed in what is “Native” vs “Non-Native”. Many Species considered “Native” to North America were very likely brought over by Native Americans but oddly corn isn’t considered “Native”?
Don’t focus on having to grow everything, supplement what you eat 1 plant at a time. Even if you get to 50% what you grow/forage you eat, is still really good!
For Zones 2 & 3, not many plants can grow in such a hard zone. I recomend creating a micro-climate that push your zone up. A huge Body of Water can extend your season for sure (Same with a Sunny Rocky Wall to reflect sunlight back). Many annuals can grow in zone 2, I’m sure you can landrace Squash to fit within your short season (Especially since Squash will ripen off vine, you can harvest it green before your first frost to finish ripening at home, + Save those seeds as they will contain genetics to ripen faster). How long is your season?
Hardiness zone is only relevant to plants that have to survive your winters, It’s not applicable to Annuals because they die reguardless & don’t have to survive your winters.
I recommend checking INaturalist to see what kind of plants are growing, just highlight your region & search for all the Plant Observations. Many of those may be wild edibles.
If you have Amelanchier growing, you can graft Apples, Pears & any other Pome fruits (Maleae Tribe).
Zone 2-3 doesn’t have much growing, but at least the spruces can make nice needle tea. Also Check Spruces & Pines for collecting pollen, a very good nutritional supplement!
Many flowers have edible uses too! But flowers are also important for pollinators & attracting beneficials! + they’re Gorgeous & a real mood booster!
But don’t Native plants also out compete Invasive too? The “Native” Blackberry is very invasive & doesn’t allow many other plants to grow through it, way more aggressive than the “Invasive” Wineberry.
Blackberries (Rubus allegheniensis & Rubus pensilvanicus species complex) are very effective at keeping deer out. I made a mistake when I cleared them out as the deer ate all my squash, melons, beans, ect. But at least I was able to grow some corn. I diversified the Blackberry Monoculture with some Black Raspberry, Wineberry, Shiso, ect.
I eventually learned my mistake & understood deer are the reason we can’t have nice things grow. My ecosystem selected for Thorny Blackberry Mess for a reason, because of deer pressure. So I let the Blackberries grow but not form a Monoculture.
Plus the Wineberries & Black Raspberries taste wayyy much better & have less thorns.
I’ve heard many plants don’t grow well under Walnuts, apparently Tomatoes was one of them? But I grew them under Black Walnuts somehow, idk.
It seems the Mycorrhiza in their root zone negates some of the Juglone effects?