Ungarland

Then on a given day, they would go and ungarland the tree, put the garlands on their own heads and walk down to the river. There they would cast the wreaths into the water, again singing a special song.

Source: wiktionary

Outwardly the first strain of parting was tempered by the arrival of Miss Mellins, Mrs. Hawkins and Johnny, who dropped in to help in the ungarlanding and tidying up of the back room.

Source: wiktionary