MARBLEHEAD – It was the site of a lead mill, a massive fire, a contaminated vacant lot, and a proposed multi-family development.Today, it is the site of an experiment that local conservationists hope will result in a meadow of native wildflowers.”We had no idea what would grow well there, so we got a whole bunch of native wildflower seeds and a whole bunch of native wildflower plants,” Don Morgan, a member of the Marblehead Conservancy, said last week. “In other words, it’s an experiment ? and next year we’ll plant more of what does well.”The Marblehead Conservancy gathered nearly 100 people May 2 at the former Chadwick Lead Mills site at the Salem and Marblehead border on Lafayette Street for the nonprofit’s annual Arbor Day/Earth Day celebration. The property was a lead mill dating from 1831 that almost completely burned in an 1897 fire, was rebuilt as a factory, and burned again in 1968, according to a master plan for the site commissioned by the Town of Marblehead.A private developer proposed developing the roughly 4-acre property in 2006 with a multi-unit housing project. But the City of Salem, Town of Marblehead, Essex County Greenbelt and the private, nonprofit Marblehead Conservancy finalized a plan to buy the property for a below-market price of $1.6 million in 2013. Marblehead voters approved a $1.5 million override that was combined with private donations and a $25,000 grant to pay for the sale.The conservancy takes care of the property, which connects roughly 60 acres of conservation land in Salem and Marblehead. The property also connects the Salem Bike Trail with the 4.5-mile Marblehead Path network.But Morgan said the property is unique among town conservation lands because it is a meadow rather than forested. As a result, the group had limited experience in what would grow in such a spot.So a group of conservancy volunteers gathered May 2 to plant some coreopsis, goldenrod, Joe-Pye Weed, cornflowers and other wildflower seeds in eight 100-square-foot plots.”We’ll water and let grow,” said Maureen Ashley, who Morgan credited with leading the effort. “It will be forever an open space, and because it’s open pasture, that’s the way we wanted to keep it.”