When the City Guide arrives in August, the Arb is glutted on sun, and the crowds are diluted by vacations elsewhere. Now’s the time to stroll beneath the lush canopy of trees and acquaint yourself with the Arb’s year-round residents. It’s home to more than 470 species of plants and trees, many identified by plastic tags that give their common and scientific names, and continent of origin. Trees range from the native and common—bur oak, hackberry—to the distant and rare—a Chinese fringe tree that, the Arb boasts, “is considered one of the best in the country.”

In September, the Arb welcomes the return of students and locals with two popular annual events: Music in the Arb (Sept. 22) is an evening of chamber music at the amphitheater, and the 3rd Annual Run for the Arb (Sept. 28) is a fundraiser 5K run/walk along its many trails. (See the monthly Ann Arbor Observer or AnnArborObserver.com for event updates and details.)

Summer’s end finds the Dow Prairie (near the river along the Arb’s eastern end) at its peak, with 12-foot-tall big bluestem grasses and many blooming wildflowers. As the weather cools in October and November, the grasses turn gold, and tawny leaves spiral off adjacent oak trees. It’s a dazzling sight, and one truly native to this part of the world.

Autumn’s cool air, in addition to burnishing leaves, ushers in migrating birds, and birders. The Washtenaw Audubon Society holds fall migration walks through the Arb every Thursday morning, beginning August 29 and continuing through October. Even in December, downy woodpeckers, cardinals, and cedar waxwings can be spied among the bare branches. Washes of green remain in several acres of coniferous forest scattered around the Arb, including a stand of pine trees that tower over the children’s playscape of Fairy Woods & Troll Hollow, near the beds that hold peonies to come.

In January and February, carpets of snow (fingers crossed) transform the Arb into a palace best explored on snowshoes or skis. There aren’t groomed trails, but plenty of people blaze their own.

When the spring sun finally appears, rejoice outdoors with a walk, even if the trails are a bit muddy. One March bloomer is the skunk cabbage, a ­pungent-smelling, red and green mottled ­flower—look for its bright green foliage in soggy areas. Spring brings a succession of blooms in the Centennial Shrub Collection near the Geddes Entrance. Eliot’s cruel April is welcomed at the Arb, breeding fragrant pink and purple lilacs, followed in May by spires and viburnums. Below these shrubs, a half-mile line of 20,000 daffodils stretches across the main valley in April. It’s an outdoor art installation planted in 2003 by artist Susan Skarsgard and 150 volunteers.

Most of the year, you can get your hands dirty volunteering at the Arb. Every second Saturday in spring, summer, and fall, the Arb holds eco-restoration workdays where you can help remove invasive species such as honeysuckle and buckthorn. Other volunteer groups include the prescribed burn crew, which uses controlled fires to keep the prairie healthy and treeless (sign up for training in October).

Late May and early June can be summed up in a word: peonies. At their peak, the ­twenty-seven beds hold about 10,000 pink, white, and fuchsia blooms. The dramatic spectacle is rivaled only by the annual Shakespeare in the Arb production: throughout June there are several roving outdoor performances of one of the Bard’s plays. When it’s too hot to move in July, you can sunbathe in the main valley, among peaceful rolling slopes, and pretend all’s right with the world. Or you can find a shady bench or picnic table overlooking the Huron River—but you might have to hunt, for Ann Arborites flock here to this most scenic part of the river’s shore.