Last year I converted some dead space in my backyard to a wildflower garden, and I started by sowing a few packets of wildflower seeds indigenous to Ohio. This summer is the first time the garden produced any meaningful amount of flowers.
I have been trying to avoid the temptation to manage the space, which would sort of defeat the purpose of creating a "wildflower" garden. After all, if I extensively weed and selectively promote the growth of certain plants over others, I am just creating another artificial landscape, albeit with flowers considered to be wild.
I did draw the line at the raspberry runners, though. If I took a laissez faire approach to the raspberries, inevitably I would just wind up with another raspberry patch, as these plants are quite hardy and they dominate a given space.