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) was Perennial Plant of the Year in 2011, and its a stunner of a fall perennial. While amsonia blooms with delicate blue flowers (hence the name blue star) in early summer, the foliage is the best feature of this plant. It’s feathery and light; it sways in the wind and flops over dramatically in a fierce rain. In fall, the pale green foliage turns a deep gold. Fans of the University of Minnesota Gophers could plant it near some maroon zinnias and make a real statement! It’s deer-resistant, drought-tolerant and 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 conditions in northern gardens. It likes a slightly alkaline soil, grows best in part shade, and brings on the 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. Anemone generally stay under 2 feet tall.
Angelica gigas — Commonly called Korean angelica, 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, cabbagelike blooms. Bees love this plant! Low maintenance, it does well in dry soils and full sun to part shade. Angelica is prone to powdery mildew, so keep it out of wet areas. One other note: Angelica is a short-lived perennial, so expect to replace it from time to time.
Verbena bonariensis — Sometimes called tall verbena or purple vervain, Verbena bonariensis is a stunning filler plant that adds height and airy bloom to late summer and fall gardens. While sometimes rated as a USDA Zone 6 of 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 have patches that continue from year to 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.