diff --git a/Documentation/config.txt b/Documentation/config.txt
index a6cd53b59c..4bb1b6f9af 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1162,7 +1162,8 @@ color.diff.<slot>::
 color.decorate.<slot>::
 	Use customized color for 'git log --decorate' output.  `<slot>` is one
 	of `branch`, `remoteBranch`, `tag`, `stash` or `HEAD` for local
-	branches, remote-tracking branches, tags, stash and HEAD, respectively.
+	branches, remote-tracking branches, tags, stash and HEAD, respectively
+	and `grafted` for grafted commits.
 
 color.grep::
 	When set to `always`, always highlight matches.  When `false` (or
diff --git a/log-tree.c b/log-tree.c
index 30706fe926..888c236aa3 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -34,6 +34,7 @@ static const char *color_decorate_slots[] = {
 	[DECORATION_REF_TAG]	= "tag",
 	[DECORATION_REF_STASH]	= "stash",
 	[DECORATION_REF_HEAD]	= "HEAD",
+	[DECORATION_GRAFTED]	= "grafted",
 };
 
 static const char *decorate_get_color(int decorate_use_color, enum decoration_type ix)