OK, so you want aggressive plants native to your zone, that probably don't look too "weedy," right? What's the sunlight and soil moisture? In general, you want to fill up the bare soil thoroughly. Any empty space invites weeds. I'd put in a selection of more showy perennials, then super low-growing perennials like violets in between, and then sprinkle the dirt with seeds of annuals like partridge pea or columbine. If you don't want to do the seeds, a good layer of mulch around the plants (but not touching them) works too. In terms of your showy perennials, black eyed susans and echinacea are classics for a reason. I have a mix of anise hyssop and beardtongue that I really like, for a more white/purple look-- they both stay nicely upright, too. Mountain mint is great for pollinators, but it's not as obviously a "flower." Goldenrod and asters are great, but they can look a little weedy if there's nothing in front of them-- the bottom leaves start to look pretty dead and grody by midsummer. If you get your flowers from a big box store, heads up that some cultivars (anything with a brand name in 'quotes') aren't nearly as good for the ecosystem. Anything that changes the flower shape/color or leaf color is just confusing to insects. Answer from spicy-mustard- on reddit.com