Fall can be stunning in the northern garden, with ornamental grasses, sedum and asters taking center stage and complimenting the changing foliage of trees and shrubs. As delightful as they are, it’s the unexpected fall beauties that I’ve been noticing recently.

Here are four perennials to consider adding to your garden for fall interest:

Amsonia

Arkansas blue star (Amsonia hubrictii), 2011 Perennial Plant of the Year, is a stunning fall perennial. While amsonia blooms with delicate blue flowers (hence the name blue star) in early summer, the foliage is this plant’s best feature. It’s feathery and light, swaying in the wind and dramatically flopping over in a fierce rain. In fall, the pale green foliage turns a deep gold. (University of Minnesota Gopher fans, plant it near maroon zinnias to unlock a new level of superfan-dom!) Deer resistant and drought tolerant, it reaches a perfect perennial border size of 3 to 4 feet tall and wide.

Japanese anemone

This Chinese native (despite its name), is well adapted to northern garden conditions. It likes slightly alkaline soil, grows best in part shade and bursts into pink just as summer is fading. The dainty blooms are a favorite of bees, and while it is not native, Japanese anemone is not invasive in our climate. I saw these near a fence at Olbrich Botanical Garden in Madison, Wis., but they would look just as sweet at a country house.  Anemones generally stay under 2 feet tall.

Korean angelica (Angelica gigas)

This tall purple presence in the garden comes into its own as the summer wanes. Its large leaves and deep purple stems add drama to the perennial border. In late summer or fall, tall spikes rise above the plant, topped with purple, cabbage-like blooms. Bees love this plant! Low maintenance, it thrives in dry soils and full sun to part shade. Angelica is prone to powdery mildew, so keep it out of wet areas. Angelica is a short-lived perennial, so expect to replace it from time to time.

Purple vervain (Verbena bonariensis)

This stunning filler plant adds height and airy blooms to late summer and fall gardens. While sometimes rated as a USDA Zone 6 or 7 perennial (compared to a zone 3 or 4 for most northern plants), purple vervain reseeds readily (in southern climates it’s a bit invasive) and many gardeners see patches reappear year after year, sometimes popping up in unexpected places. Verbena bonariensis is a very attractive plant to bees, butterflies and hummingbirds, and looks great at the back of cottage-style borders. It likes full sun and does fine in most soils.

If your garden looks a little drab this year, try some of the unexpected and lovely fall perennials.