The flowers on this garden phlox open light blue, deepen to violet-blue, and look bluer in morning and evening light than at midday. Phlox paniculata 'Blue Paradise' grows 2 to 3 feet tall and 1 to 2 feet wide in full sun, hardy from Zone 4 through Zone 8, and reaches full size in its second or third summer.
Blue Paradise is strongly fragrant and starts flowering in early July. Its mildew tolerance is good where air moves freely around the plant.
Garden phlox, Phlox paniculata, grows wild across the eastern and central United States along stream banks, in open woods and in damp meadows, and gardeners grew it long before anyone bred a series of it. Each flower is a narrow tube with nectar at the base, built for long tongues, so swallowtails, fritillaries, hummingbird moths and hummingbirds visit through midsummer. The plant dies to the ground in winter and comes back from the roots a little wider each year. Even mildew-resistant phlox stay cleanest with space between plants and air moving freely through the stems.
The color shift shows best where the plant is seen in morning or evening light, near a patio or a window.