I had the wrong species name for my plant, it is Vernonia noveboracensis. You must have the cultivar Vernonia lettermanii 'Iron Butterfly '. It's a clone of a selection that was shorter and more compact than the species. Any seedlings from your Iron Butterfly will be taller and slightly different than the plant you purchased. It's a good idea to cut the plant back early in the season so it won't flop. If they aren't cut back they can flop and become a doughnut shape. I cut my plant back severely 1 time this year, but I could have done it a second time, it still grew to about 4 feet, but is bushy enough to not flop. Vernonia species will hybridize easily, so it's possible the wild one can hybridize with yours, but I wouldn't worry about it, you might end up with some beautiful hybrids. This is where wild Vernonia lettermanii grows, in novaculite rock along a river running though mountains in Arkansas and Oklahoma. They grow out of cracks in the rocks and sometimes get flooded, so they need good drainage, but can handle periodic flooding. Iron butterfly should do well in regular garden soil, so they claim. The Chicago Botanical Garden did a comparative study of different Vernonia cultivars including Iron Butterfly. Photos by the amazing Adam Black

You'll have to kill the grass first in order to not have it take over again, the flowers soon die out. With environmental conditions present here tending greatly to favor the prevailing of grasses over flowers - all the more so because of all the weedy Eurasian grasses that are around. So that even in the minority of local sites such as bedrock outcroppings and certain other naturally treeless locations where shallow or dry soils have allowed the persistence of numbers of native meadow flowers invasion by weedy grasses and other threats is often occurring. As it happens I did a garden consultation this year in Skagit County, Washington where the client had had the same idea as you. The wildflowers had been planted and were flowering in the part of the field where the septic was. Vigorous grasses were present all around the planted section, I don't remember what the preparation method was but it certainly looked like the scheme was not going to last unless periodically redone. Also the "northwest wildflowers" were all kinds like might be seen growing natively in the Siskiyou-Klamath area or even farther south in California; at least they weren't the various Old World species typical of wildflower mixes offered and planted in our region. But the point remains that checking to see which particular species a mix being considered contains is an important aspect. At least where a body is trying to support the local ecology, as you apparently are.

Oh, it's very difficult to define. According to the photo, only experienced biologists will help you determine the type of this wild plant, especially when I was driving through San Antonio, I saw many different types of such plants, and I would not say that they are very different in some way :) As for flowers and plants, I am not a special expert here, but I think that on this forum, you will find knowledgeable people who will prompt and help you. Even when I met a girl, I rarely gave her flowers. If I did, I turned to the Mississauga flower delivery service since this service makes unusual bouquets that even attracted me.

It doesn't look like a wildflower and may not even be from this mix You are correct - it is a woody plant, with the specimen shown predating October. And if you are located in North America: This aggressive grower poses a threat to native plants and communities. Its vigorous growth forms mats of monotypic evergreen groundcover that displaces and excludes most other plants, including native wildflowers. Extensive infestations can be found under forest canopies. https://www.invasive.org/weedcd/pdfs/wow/common-periwinkle.pdf