Pittsburghers usually call it “phlox,” or—as we have heard a Pittsburgher say—“some sort of phlock.” But this ubiquitous late-spring flower is really a member of the mustard or crucifer family, as you can tell by the four-petaled flowers (real Phlox flowers have five petals). It came from Europe as a garden flower and quickly made itself at home. It would be hard to conjure up any inhospitable feelings toward this welcome guest, whose bright flowers decorate roadsides and back yards everywhere. Each colony blooms in a mixture of colors from deep magenta to white, and many plants grow flowers with splashes or stripes of contrasting colors. The flowers in these pictures were blooming in late May; the solid colors were in Mount Lebanon, and the bicolors in Beechview.
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Gray describes the genus and the species:
HESPERIS [Tourn.] L. ROCKET. Pod linear, nearly cylindrical; stigma lobed, erect. Seeds in 1 row in each cell, oblong, marginless. Cotyledons incumbent. Biennial or perennial, with serrate sessile or petiolate leaves, and large purple flowers. (Name from hespera, evening, from the evening fragrance of the flowers.)
H. matronalis L. (DAME’S VIOLET.) Tall: leaves lanceolate, acuminate; pods 5-10 cm. long, spreading. Sometimes cultivated, and spreading to roadsides, etc. (Introd. from Eu.)