There is a lot to be said for trees that bloom in summer, "long after all the spring flash is gone," says Barbara Selemon, plant propagator at the University of Washington Botanic Garden in Seattle. Chaste tree blooms in June in the South but not until August in the Pacific Northwest, where its luminous lavender spikes of flowers are a welcome sight in verdant late-summer gardens. The flowers appear on 6-inch wands above lush, gray-green foliage, and the effect is elegant and lively. Chaste tree grows up to about 20 feet tall and wide in the South, but only to about half that size in Seattle; at the Washington Park Arboretum, it is planted near a path so its flowers can be appreciated up close. "It grows in an area where it gets almost no water," Selemon says, "and it needs almost no care." Grow in sun. Hardy in Zones 6 to 9; it grows as a dieback plant in colder areas.