The "Garden" in the song is indeed the Garden of Gethsemane. My wife and I are going through Alfred Smith's wonderful
Treasury of Hymn Histories in our devotions together, and recently read this song's history. (Al Smith was the founder of Singspiration and a family friend--
http://livinghymns.org/bio.htm.) It was written just after the author had been in Gethsemane on a Holy Land trip, and was deeply impressed by remembering that the Lord had prayed there.
This song should be categorized as a "testimony song" rather than a hymn. Unfortunately, few young people nowadays know enough about the traditional songs of the faith to make these distinctions. I urge all of you young folk to study the old songs a little more before rejecting them.
Furthermore, among IFBs, there are many new songs being written in the style of the old hymns, testimony songs and Gospel songs. (This last category is not the same as the modern term, but was a common term during the days of the Moody-Sankey campaigns.) The church where I now go and its college, where I now go, has an incredible music program, with a genuine music school teaching voice and many instruments in addition to the church and college programs. The teachers here are writing many beautiful songs in the revival tradition which we enjoy in every service.