Tropicals provide an instant impact upon installation, and enjoyment for the entire growing season.
Japanese Fiber Banana has glossy banana leaves up to 6' long in one season. The fruits of Musa basjoo are not edible, but the plant overwinters in a sheltered location if heavily, deeply mulched (the one time mulch volcanoes are appropriate...). Per Bruce Crawford, the common name is deceptive because Japanese Fiber Banana is actually native to China.
'Black and Blue' Anise-Scented Sage starts blooming in July and continues until the first frosts. The showy flowers are a deep cobalt blue, set off by black calyces. They are produced in great numbers on long spikes above shiny green foliage. Like other large flowered Salvias, 'Black and Blue' is an amazing hummingbird and Sphinx Moth magnet. Give it plenty of room in the late summer garden, as it is a sprawler. With lots of mulch, Salvia 'Black and Blue' has been known to overwinter in Zone 6 and 7.
Tall Verbena or Brazilian Vervain is not a hardy perennial for the Mid Atlantic area, but this beautiful annual self-seeds vigorously in perennial beds. The clumps of tiny purple flowers are held on tall thin stems and make a lovely airy show from July through September. Butterflies love the late season flowers and they make a pretty addition to cut flowers because of the long clean stems. We enjoy this tough reappearing annual in our gardens year after year.