By Cmoore
Vermont,
United States 
I would like to prune my rhodedendruns. When is the best time to do this and how do I do it?
15 Jun, 2010
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Rhododendrons don't need much pruning generally, but if you do, do it just after they have flowered. Leave it too long after they have flowered and you will be removing next year's flowers.
If however you are looking for a major overhaul of the entire plant then this is best done over several years. This link to the RHS website may help give you more detail.
http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=529
18 Jun, 2010