Hundreds of spectators are expected to visit Dorchester Park this Sunday evening for a free, outdoor classical concert that will feature the music of George Gershwin and Gospel favorites, a contest for most creative picnic and an official ceremony marking Dorchester Park as a historic site. The Boston Landmarks Orchestra, led by conductor Charles Ansbacher, will headline the festivities, which will begin at 6:30 p.m. at Dorchester Park's main baseball field.

The concert is fast becoming a mid-summer tradition at Dorchester Park, the Olmstead-designed green space that straddles Cedar Grove and Lower Mills. The orchestra has played the park for four consecutive years and crowds have been steadily building each year. This year's program will include selections from Gershwin's "Porgy and Bess" and "An American in Paris" compositions, along with a variety of Gospel selections done in collaboration with the Berklee College of Music.

The Boston Landmarks Orchestra - founded in 2000 - stages music performances in "significant architectural, historical, and geographical settings throughout the Boston area," according to its web site. The orchestra is led by Charles Ansbacher, who is also the Principal Guest Conductor of the Moscow Symphony Orchestra. Ansbacher has conducted the Vienna State Opera, the Vienna Chamber Orchestra, and members of the Chicago Symphony Orchestra, in cities all over the world.

Owned by the city of Boston, Dorchester Park has been carefully restored in the last decade under the Menino administration and with the support of an active friends group which has helped to raise funds for its preservation. An ad-hoc committee of neighbors, including Dorchester Park Association President Jane Boyer, Boston Landmarks Orchestra board member Bill Walczak and Reporter Publisher Ed Forry, have been active in organizing this season's concert, which is sponsored primarily by Bank of America and the city of Boston's Parks and Recreation Department.

Mayor Menino will be among those judging this year's best picnic contest. Many concert-goers pack picnics - along with blankets and lawn chairs - to make an evening of it at the event. Beginning at 5:30 p.m., judges will look for picnic standouts in the categories of most community spirit, best presentation and most original.

Mayor Menino will also be on hand at the concert to unveil a plaque that will be mounted at the park this summer. The plaque denotes the park's recent admission to the Registry of Historic Places, a process that took years to achieve. The park, designed by renowned landscape architect Frederick Law Olmstead in 1891, is roughly 26 acres and includes two baseball fields, tennis courts, a childrens' play area, and tree-lined paths.

In a first this year, free parking will be available for concert-goers in Carney Hospital's rear parking lot. The lot now has direct accessibility to Dot Park through a gate that leads to the concert site.

For more information on the orchestra, check out their website at landmarksorchestra.org