Not all invasive, exotic plants, aliens, immigrants, are bad. The Deptford pink (Dianthus armeria) isn't a problem of any sort that TPP knows of and it makes itself quite at home in a prairie. It appears to blend into the forb ensemble quite amicably. Mostly it goes unnoticed because it's a very slender, small-leafed plant up to about 2-2.5 feet tall topped by some very pretty, but very small flowers (about 1 cm in diameter). It would be a nice addition to a wild flower perennial garden, and will grow in some very poor soil under pretty dry conditions. The plant sways easily in the wind, and since the target is small, photographing the flowers in the field is a challenge; here's a shot that was grabbed while collecting data the other week. Like pinks in general the petals are notched or toothed at the apex, and in this species pink petals splotched with white. Deptford is a town in the UK where this plant grew abundantly; somehow this name stuck with it in North America. Our local variety tends to be a bit paler pink than populations elsewhere.