According to this article the years between 1962 and 1967 saw changes in grammar learning in the United States. The “section[s] on diagramming sentences was expelled from the 1967 sixth edition, never to return.” The 5th edition, of which I have two copies, and to which I often refer, was published in 1962. It still contains sentence diagramming.
http://m.metropulse.com/news/2011/jun/15/how-harbrace-handbook-english-changed-way-american/
