A friend was told that pinching out growth buds before they begin to elongate as a means of shaping young rhododendrons would only stimulate buds further down the stems that were less than 4 years old – older than that and the growth buds would no longer be viable. I cannot find any information to suggest 4 years viability of dormant buds to be true, or untrue. Can you help?
Though pinching encourages multiple branching lower down the stem, I find no reference to it being done at a particular age.
“This practice (pinching) is recommended for most larger rhododendrons until they reach flowering size…”
(Source: A Plantsman’s Guide to Rhododendrons, by K. Cox, 1989, p. 101)
That statement indicates a younger plant, but the author then mentions several exceptions.
Here is some how-to information about pruning online: