I have some ground phlox that bloom in the spring, and then I have a weird hybrid, not even two feet tall, white, that bloomed a few weeks ago but won't bloom again the rest of the year even if I pick back the spent blossoms, plus it never reseeds itself and it doesn't grow wider. And then I have my standard tall phlox that Nothing Can Kill (TM), that blooms from now until nearly October, mostly a lovely pink with an occasional Miss Lindgard white one sneaking in. The pink ones are so strong they overwhelm the other colors, which tend to vanish. If the deer don't eat them, these phlox will do their best to take over the world. I have them in with the echinaceas and rudbeckias and some artmeisia, though, and they also are doing their best to take over the world. Not to mention mistflower and various tall weeds. It's a fight to the finish.
I have a few white echinaceas but most are pink. I've seen some interesting hybrids with other colors but I figured the pink would overwhelm them, and anyway, I don't have much room for new plants and certainly no dirt.
I think I discovered that a persistent weed in the front yard is St. John's wort. Maybe 18 inches tall, with a bunch of small yellow flowers. On the whole, I approve of yellow flowers, but I'm getting rid of the mulleins because they are non-native invasives. I pulled out 37 in just one patch--1 main plant and 36 babies. Tilting at windmills, considering they can be found on every other piece of land around here.