The Central Spine of a New Neighborhood

Commonwealth Avenue and its Mall were part of the bold plan to fill Boston’s Back Bay, one of the greatest examples of urban planning in America. Beginning in 1857 and continuing for nearly forty years, new land was made from gravel brought by train from Needham. At the height of the Back Bay’s creation, trains arrived every forty-five minutes, and two new house lots were created each day.

The new streets were laid out in a grid pattern according to an 1856 plan by architect Arthur Gilman, who was only in his twenties but well traveled. Inspired by Parisian boulevards and London’s green squares, Gilman designed long, wide straight streets with extended vistas and a strong central axis. The core of his plan was Commonwealth Avenue and its grassy Mall, designed to create a straight-line vista beneath a canopy of four rows of elm trees.

A Noble Central Avenue

Wide, straight, and paved with crushed stone, this “noble central avenue” was an immediate draw for promenades, carriage races, and parades, as well as a route to the open country. It served as a model for boulevards across America. Linking the parklands of the Public Garden with those of the Fens, the Mall would come to form a precious link in Boston’s “Emerald Necklace.”

The street was the site of the grandest new mansions, setting a tone of elegance for the entire district. The houses had to be set back twenty feet from the property line, giving extra breadth to the two-hundred-foot-wide boulevard with its two roadways and central Mall. The variety of building styles was unified by the trees on the Mall; the architecture and planting reinforce each other in a unique and powerful way. The green corridor of the Mall enhances and complements some of the country’s finest examples of nineteenth-century residential architecture.Contrary to popular belief, Frederick Law Olmsted had nothing to do with the Mall’s original design.

Contrary to popular belief, Frederick Law Olmsted had nothing to do with the Mall’s original design. In 1880, however, he and Charles Sprague Sargent, his partner in creating the Arnold Arboretum, were asked for their advice on the tree planting patterns. They proposed removing the existing four rows of American and European elms and replacing them with two single rows of European elms. The City Council rejected the proposal, however, fearing a public outcry.

Olmsted did design Commonwealth Avenue west of Massachusetts Avenue, making a curving transition between the formal boulevard and the informal park at the western end. The work was completed in 1885, but the area later had to be redesigned.

The Mall in the Twentieth Century

In 1921, a formal and straight continuation of Commonwealth Avenue, including a tree-lined mall, was designed by Arthur Shurcliff, who also did the 1937 underpass at Massachusetts Avenue. The underpass moved traffic faster, but it destroyed the continuity of the central promenade, making it impossible to walk the full length. Many people today do not realize that the Charlesgate block is an important and historic part of the Mall.

By the late 1960s, Dutch elm disease was a full-blown threat on the Mall, attacking the elms to such an extent that almost half of the 600 elms on the Mall were killed by the disease, leaving blocks with only three or four trees. A major effort of the Friends in the early decades of the organization was the gradual replanting and treatment of the Mall’s trees, with disease-resistant elms but more importantly with a variety of canopy trees that have a compatible form but bring in the diversity that will guard against future disease threats. Today, tree species include elm, zelkova, oak, maple, ash, sophora, and sweet gum.

The Mall, originally designed for gentle use by promenaders, is now a major civic space, the site of huge events such as charity walks and the Marathon, as well as a valued amenity for residents, workers at local businesses, and a destination for visitors and tourists.

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