But the long-term perennials, suited to the environment, are mostly missing. The truth is, creating a little piece of self-sustaining ecosystem is not easy. After all, it has taken many years and millions of dollars in mowing machines, earthmovers, herbicides, and public works salaries, to eliminate almost all the native habitat from road and trackside, field and suburb. Restoration takes time and knowledge. Local native seed is expensive because it's difficult to collect.
Diversity is essential to success, but unpredictable.
When a planting is done right from the start, however, the payoff comes after three or four years, when enough different flowers and grasses have succeeded to provide interest during all seasons, and no one species has been able to dominate all others. Of the few perennials in those generic mixes, one species will have become dominant by the fourth year, resulting in a non-native monoculture that blooms only for a few weeks. Shasta Daisy is a commonly used weedy horticultural. Bachelor's Button and Baby's Breath have caused problems in some Wisconsin areas. One of the worst choices is Dame's Rocket, a Eurasian mustard.