I saw this in The Guardian:
Who held the first Memorial Day celebration?
African Americans have fought and died for America from its earliest days, from frontier skirmishes to the French and Indian Wars to the fall of Crispus Attucks at the Boston Massacre, immortalized as “the first to die for American freedom”. And though most official histories of Memorial Day credit with its founding a white former Union Army major general, whose 1868 call for a Decoration Day was reputedly inspired by local celebrations begun as early as 1866, the first people who used ritual to honor this country’s war dead were the formerly enslaved black community of Charleston, South Carolina in May 1865 – with a tribute to the fallen dead and to the gift of freedom.
There are some good links here.