The donation, made by a local foundation with the stipulation that its name remain anonymous, will be used to hire a full-time project manager and an assistant, and pay for other expenses, including the development of gardens at its Wellesley headquarters. A portion of the money will also be used to produce the society's premier event, the New England Spring Flower Show, and pay for the redesign of the group's website.

The three Greenway parcels, which were designated for the horticultural society's use, have been surrounded by controversy over their development. One of the parcels had been scheduled to be used for a botanical garden known as the Darwin Project but that plan withered after planners responsible for its development resigned from the project earlier this year.

The development of the Greenway suffered another setback earlier this month when the YMCA of Greater Boston announced that increasing construction costs had forced it to withdraw its proposal to build a major recreational facility in the North End near the Greenway corridor. YMCA officials said that in the two years that project has been under development, the cost of the four-story facility jumped from around $40 million to $70 million, primarily due to the added expense of building over highway ramps leading to the Central Artery.