It sure is hard to define "widlflower"...
Wild where? If it has only been imported here three hundred years but it is everywhere now, is it a wildflower, or an invasive? Alex raises a good point about all natives being good and vice versa; many non-natives are less intrusive or damaging to local environment than "native" plants moving in in monocultural fashion. But how can
Robinia be invasive to Connecticut when it is in our fossil seed record? Sure it got knocked out by glaciers a couple of thousand years back, but it's returning, right? Return of the prodigal tree... And how is
Phragmites invasive if it is circumboreal (found all around the world); isn't it just a vigourous native?
But the reality of exotic genotypic variance and anthropogenic dispersal having some calamitous ecological effects is pretty evident in America's Eastern forests, and entirely at the hands of the horticultural trades. From elms (Dutch Elm disease) to chesnut (Chesnut blight), to hemlock (wooly adelgid), we have imported devastating blows to local ecology in the interest of new gardening plants. How can we envision the local ecology of three hundred years ago with these gaps we have created? We cannot; they are tragic losses that we should work diligently to ensure are not repeated. Only the hand of Man can temper the hand of Man...
Now I am a gardener, one fond of Japanese gardening and many of the plants used in Japan. I love these plants as much as my native horde, but I have selected them carefully for their ability to play nicely as much as any aesthetic attribute. I do not use invasive plants and do not recommend them for any reason. Mixes in a can don't show that kind of control, so I'm not a fan. Alex's points aside, I think we can do better, and if you are going to do wilflowers, a quick assessment of the rest of the biota seems a good idea. Are you trying to attract a certain species and should you? Cardinals were rare when in Connecticut when I was a child, but supplied feeding has helped them move north. Is that good? Bad? Maybe generally supportive plants are best for the environment? How do we pick those?
Work by some smart fellers suggests that natives are the most ecologically supportive plants; Doug Tallamy's work is very interesting...
[url]https://www.wildflowersmich.org/assets/docs/09_wnl.pdf[/url]
Doug's a friend of a friend who just wrote this wonderful book (Rick Darke who wrote the forward is another wonderful touchstone on this topic)
[url]https://www.timberpress.com/books/isbn.cfm/9780881928549[/url]
Doug's not just some hack...
Tallamy is currently Professor and Chair of the Department of Entomology and Wildlife Ecology at the University of Delaware in Newark, Delaware, where he has written more than 65 research articles and has taught insect taxonomy, behavioral ecology, and other subjects. Chief among his research goals is to better understand the many ways insects interact with plants and how such interactions determine the diversity of animal communities.
So do some homework on what is actually around in your neighborhood, both flora and fauna. Be aware of whether the plant you are purchasing is invasive or not, and every once and a while, think about REAL wildflowers as a choice...
Michelle, solarize the area (black plastic for like two sunnier weeks) which will kill the seed. Better off doing starts than scattering seed anyway (get your design on, girl...

). Check your state or local watershed resources; you can sometimes get local seedsourced plants...is Echinacea native around me? Not really, but it's close, I have one...find natives you like as well, it's a garden. Want to put a non-native in? Fine by me as long as I'm not picking it out of my yard in a couple of years...
HG